Fic: Difficulties in Mathematics (1/2) (Gen, G)

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Title: Difficulties in Mathematics
Author: jadesfire2808
Recipient: with_apostrophe. Hope this comes to close to what you wanted!
Pairing: None/Gen
Rating: G
Word Count: ~13,800
Spoilers: Set soon after "The Shrine" and relies on knowledge of that episode, as well as mention of "The Prodigal".

Notes: With more thanks than I can express to my betas, who know who they are. You guys have the patience of saints and the observation skills of copy-editors. Couldn't have done it without you.
Disclaimer: I don't own the laws of physics, I just like breaking them for fictional purposes. With apologies to Albert Einstein.

Summary:

Rodney paused, trying to think how he was going to explain without causing a general panic. Tact was probably called for and it would be as well to watch his words until he was absolutely sure about what was going on.

Of course, the words that actually came out of his mouth were, "Atlantis is about to be sucked into a black hole."

Difficulties in Mathematics

Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.
Albert Einstein

NOW

Sheppard caught at Rodney's arm as they skidded round another corner.

"Careful."

Panting hard - because he was fairly sure Jennifer had said "light duties only" after his, oh yes, brain surgery last week - Rodney nodded, not wanting to spare breath for words. He could hear Ronon and Teyla behind them, keeping pace with their mad dash. Normally, Rodney could run for his life with the best of them, and he hated, hated being the one to slow them down, but his head was starting to spin and it was only the gentle pressure of Sheppard's hand that was keeping him upright and headed in the right direction at this point.

He groaned gratefully when the tablet that Teyla was carrying beeped again and they all slowed for her to read it. Waving away Sheppard's worried look, Rodney put his hand on the wall and tried to remember how to breathe.

"Jeannie says that the dilation field is expanding," Teyla reported, and Rodney was petty enough to be pleased that even she sounded a little winded. "She and Zelenka estimate that the whole of Atlantis will be affected within twelve of their minutes."

"Which is how long for us?" Sheppard asked, and Rodney groaned again because how many more times?

"We've got no way of knowing that accurately," he said between gasps. "What's Radek's estimate on relative times now?"

It took Teyla a moment to find the answer, and Rodney tried to ignore the way Ronon was still pacing the hallway impatiently.

"Twenty minutes for every two hundred meters," she said at last, looking up at him as though he would know whether or not that was correct. Even he had trouble running those kinds of numbers in his head, but it sounded about right.

"Shouldn't we keep moving?" Ronon asked, coat swirling as he turned to pace back again.

Rodney groaned again. "Time's relative now. If it's slowing that much the closer we get, then we've got hours from our point of view here. Once we start moving, we'll have less time, and once we get there-" He stopped, seeing the blank look on Ronon's face. "Never mind." His heartbeat was loud in his ears still, but it seemed to be coming closer to a normal speed, so it was probably time to get going again.

He didn't complain when Sheppard pulled him upright again, dragging him on down the corridors. Because even if everything was relative, they were still going to lose the city and everyone in it. Sooner or later was kind of irrelevant, really.

*****

BEFORE

The only thing Rodney found comforting about this whole situation was that Sheppard was even worse at saying goodbye than he was. If he wasn't trotting out platitudes like "good to see you" (and what was that about? They'd called his sister here from another galaxy to watch him die. Since when was that good?) or wishing her a "safe journey" (they were sending her through the Stargate. What was she going to do, trip over it?), then he was grinning and nodding as though his head might fall off if he stopped. It was getting embarrassing, and Rodney was actually relieved when Rangan announced that his team and equipment were ready.

"Finally," Rodney muttered, earning him a look from Teyla. He shuffled his feet and resisted the urge to glance at his watch. It wasn't that he wanted to get rid of Jeannie - he'd agreed to try to get home for Christmas next year, hadn't he? - it was just that having her here was yet another delay to his getting back to work, not to mention a constant reminder of why she'd been here in the first place. They could exchange emails, couldn't they?

He looked down into the gateroom where the botanists were still checking lists and reading labels on boxes. It wasn't often that he was grateful to the botany department, but their need to get those samples back to Earth quickly at least meant that Jeannie would have a short trip home. No waiting around for the Daedalus to get here, either, which was definitely a good thing. If she told his team many more stories about him, they were going to have enough ammunition for about the next century.

"Mer?" The look on Jeannie's face suggested she'd been saying his name for a while, and he shook his head apologetically, immediately regretting the decision when a wave of nausea washed over him.

He waved away her concerned look. "I'm fine, just..." Gingerly, he ran a hand over the bandage on his forehead. "I'll be fine."

"I know." Her hug was gentle, careful, as though he might break if she squeezed too tight. "Take care of yourself."

"I always try to." He shoved his hands in his pockets as soon as she stepped away, and he watched awkwardly as she said goodbye to the others. Honestly, you'd think she'd been here ten years not ten days. How did she do that?

Idly, he ran his eyes over the computer screens that he could see, automatically noting power usage and the most basic of sensor readings. He could just about see the ZPM usage monitor, and was leaning over for a better look when Woolsey said, "Dial the gate."

Rodney blinked. Something registered at the back of his mind, and he was saying, "Stop. Stop dialing right now," before Chuck had pressed the third symbol and almost before he knew what he was doing. There had been something, though. He'd seen it.

"Rodney?"

Still blinking, Rodney looked over at Sheppard, not really seeing him. "I thought I saw..." He trailed off. The line of the graph was smooth again. He'd probably imagined it.

"If you don't mind?" Woolsey was looking at him, one eyebrow raised, and Rodney deflated a little. Automatically, he rubbed at the bandage on his forehead, where the medical tape was making him itch.

"Sure." He waved his hand vaguely, aware of the way Sheppard and Jeannie kept looking at each other then at him. Maybe he was just imagining things, and he really didn't feel properly well yet. But as Chuck finished the dialing sequence for Earth, he saw it again, that tiny blip on the screen that rang alarm bells in his head. He'd actually opened his mouth to say something when Chuck hit the activate button and everything seemed to happen at once.

There was an almighty bang from down in the gateroom, people began yelling and all the lights went out. Showers of sparks flew from the consoles at the back of the control room, and Rodney wrapped his arms around Jeannie, trying to shield her as the first explosion was followed by a second and third, taking out two monitors and plunging them further into darkness. Rodney dropped to his knees automatically, Jeannie still cradled against him, as Sheppard hurried across the room to duck down next to them, pushing them both into the shelter of the console as crystals began to blow.

"I don't think it's supposed to do that," Sheppard yelled over the noise, flinching as something exploded right above them.

"You think?" Rodney yelped as a piece of ceiling plate came crashing down behind Sheppard. "Next time, maybe you'll listen to me!"

"Next time, maybe you'll actually tell us what the problem is!"

"I was going to, but everyone looked at me like I was crazy."

"Since when has that stopped you?"

"Would you two shut up?" Twisting in Rodney's arms, Jeannie pushed her hair out of her face and glared at them both. "What the hell is going on?"

The sudden silence was almost as startling as the explosions had been, and no one moved for a moment, as though waiting for it all to begin again. When it didn't, Sheppard looked one way then the other, then slowly shifted backwards.

"Everyone okay?" he called, helping Jeannie to her feet and completely ignoring the hand Rodney waved in his direction. "Mr Woolsey?"

"Here."

Struggling to his feet, Rodney eventually located Woolsey behind Ronon, probably explaining why his voice was slightly muffled. Teyla seemed fine, with only a loose strand of hair to suggest that anything untoward had happened. Around the room, people were groaning and sitting up, looking a little singed around the edges but generally in one piece. The consoles themselves were a mess, and the air was filled with acrid smoke.

"Well," Rodney said, brushing some dust from the top of his head, "that went well."

*****

NOW

The irony was, of course, the closer they got, the longer it was taking them to do anything, relative to the rest of the galaxy, anyway. Time dilation had been bad enough when Sheppard had been stuck with those weird Ancient wannabes, but like this, with the field strength changing with every step they took, even Rodney was starting to lose track of what was happening when. For lack of a better explanation, he decided it was best to think about things happening one after the other, without worrying too much about how long it was taking or what everyone else in the city was experiencing. There was no way for him to know, and worrying wasn't going to solve that. He needed to focus on one thing then the next thing and not get distracted.

Everything was relative now, anyway, and the only time that mattered was their own. Fortunately, thanks to Sheppard's hand on his arm and the constant undertone of Ronon's muttering behind him, Rodney was just about managing to keep up, and they were halfway down the south pier before he had to call another halt. He guessed it was about ten minutes since their last contact from Jeannie, so he was surprised when the tablet beeped almost at once. The relief at hearing from her was not something he was admitting to.

"The field's getting stronger," he said, leaning against the wall. "That didn't take anywhere near as long as it should have, not if they're updating us every eight hours."

"Well, we're getting closer, so that's what's meant to happen, right?" Sheppard didn't sound at all sure and when Rodney looked over, he was frowning again. "Shouldn't we be hurrying up?"

"I swear, if anyone asks me that one more time I'm gonna-"

"Jeannie says that the effects have reached the tower," Teyla interrupted, and Rodney saw Sheppard open his mouth to ask. This was getting painful.

"They can use the light from the stars to tell," he said quickly. "Just...trust me on this one, okay? But you're right, we need to move if we're going to stop this before we have a full blown black hole right here in the city."

"I thought there was no hurry," Ronon said, shifting his grip on the box he was carrying.

Since it would probably set his recovery back, Rodney resisted the urge to bang his head against the wall. "I swear, when we get back, I will explain it in words small enough for you to understand. Right now, we need to move."

"You were the one who stopped," Sheppard pointed out, completely unnecessarily, but he tucked his hand under Rodney's elbow again, pulling him down the corridor behind Ronon, who seemed to have set off at a run.

"If the city does get sucked into a black hole, I'm probably not going to get put back on active duty, am I?" Rodney said, trying not to trip over his own feet.

Sheppard snorted. "Look on the bright side, why don't you?"

"Hey, at least I'd get to sleep in."

*****

BEFORE

Twenty minutes later, and Rodney had just about managed to get two computers up and running, as well as restoring the emergency radio channels. Well, Jeannie helped with that part, and now she was helping one of the new staff - Amanda? Amy? - to collate damage reports and get some of the critical systems up and running again.

"Mostly we've just lost power," she said, coming over to where Rodney and Sheppard were trying to get internal sensors online again. "The control room is the only place that actually seems to have been damaged at this point."

Rodney frowned. "Wasn't Zelenka checking the ZPM room? Is he really saying that everything's fine down there?"

Shrugging, Jeannie checked the computer she was carrying. "He hasn't reported in yet."

That caught even Sheppard's attention and he looked up from the console. "Wasn't he down in the astrophysics lab?"

"I thought so." Feeling a tendril of fear creep along his spine, Rodney reached for the radio that wasn't actually in his ear. He turned to the comm console. "Patch me through to Zelenka."

"We don't have speakers, sir," the harried-looking technician said, reaching to connect him anyway.

"Here." Sheppard passed across his earpiece, and Rodney started talking even before he'd put it on.

"Radek, what the hell are you doing? I told you to get down to the ZPM room. How are you getting there, by snail?"

"Meredith!" Jeannie was glaring at him, but Rodney just shook his head.

"It's like, a ten minute stroll and no one in this city should be moving at less than a sprint right now. Radek!"

There was an odd squeaking on the line, then it went silent again. Frowning, Rodney turned to the technician.

"Are you sure you're on the right channel?"

"It's the only one we've got, sir."

"What is it?" As Sheppard came over, Rodney took the radio out of his ear again, dialing up the volume so that Sheppard and Jeannie could hear.

"Radek, please respond."

There was a slight pause, then the squeaks again. Glaring at the radio wasn't help much, but as he did so, Rodney felt something in his brain click. His face must have given him away because when he looked up, he saw his own fear mirrored in Sheppard's eyes.

"Rodney?"

Shaking his head, Rodney waved at the technician. "Can you slow the transmission down? I mean, really slow it down. Say, ten times slower."

In the end, they had to patch the laptop into the console to make it work, and it took them three tries to get the speed right. Jeannie hit the right one in the end, and she started to run the code as Rodney spoke into the radio, as quickly as he could.

"Radek, this is Rodney, we know things are going wrong and we think we know what's going wrong, but we really, really need you to report to us from the ZPM room right now. Please respond as soon as you can and speak as slowly as you can."

They waited for a few long seconds that stretched out into a minute. Rodney bounced a little on his toes, feeling his pulse in the scar on his forehead, the itch of sweat under the medical tape. If he was right - and there wasn't much 'if' about it - then they were going to need a plan, and fast. Or possibly not. Damn, this was going to be confusing.

After another thirty seconds, in which Woolsey came over to join them and was shushed into silence by Sheppard, Radek's reply came over the laptop's speakers, tinny and still too high-pitched.

"Rodney, I am moving as quickly as I can but I have only just reached the ZPM room. More messages do not make me move faster. There is considerable damage here and it will take me some time to establish what the problem is. Also, I think there is something wrong with your radio. Please repeat your last transmission."

"Oh boy." Taking a deep breath, Rodney turned to the sensor console where Chuck and an engineer had taken over his and Sheppard's work. "Are we online yet?"

"Nearly, sir." Ducking under the console again, there was a click as Chuck slid a crystal into place and the console lit up, almost too bright in the gloom.

"Would someone mind telling me what's going on here?" Woolsey looked like a man at the end of his patience, and Rodney supposed he'd be kind of ticked off if someone had blown up his control room. Oh wait, they had. Shaking his head, carefully this time, he opened his mouth to speak into the radio when Zelenka's voice came through again, even faster this time.

"Give me a minute." It took Jeannie a few seconds to compensate, then everyone leaned in to hear.

"Rodney. There is a serious problem with the ZPM. My watch-"

Rodney hit the button to break into the transmission, almost garbling his words as he yelled into the radio, "Radek, you brain-dead moron, forget your watch, okay? The watch is not important. We know, alright, and we'll find a way to fix it, just get yourself and anyone with you up to the control room right the hell now."

He took his finger of the transmit button, suddenly aware of everyone staring at him.

"Rodney," Sheppard said, with that carefully controlled tone he used when he was really, really ticked off, "what is going on?"

Instead of answering, Rodney looked sideways at Jeannie, and could see in her face that she knew. It was actually a relief, to know that he wasn't imagining it, that his mind wasn't playing tricks on him, that this really was happening. Her hands rested lightly on the laptop keys, and she looked as though she was holding herself steady only with great effort. When she looked up at him, he nodded to her silent question and God help him but Rodney was almost glad she was there because at least someone in the room was actually going to be able to keep up.

He paused, trying to think how he was going to explain without causing a general panic. Tact was probably called for and it would be as well to watch his words until he was absolutely sure about what was going on.

Of course, the words that actually came out of his mouth were, "Atlantis is about to be sucked into a black hole."

*****

NOW

"Is it just me, or is this getting harder?"

Sheppard was panting, his face and ears red with exertion.

Trying to breathe steadily, Rodney shook his head. "It's not you. We're getting close to the event horizon or whatever the hell it is. The gravity's stronger down here, which is why time's slower. Sort of. It's probably going to get worse before we get there."

"Great." The veins were standing out on Ronon's arms, muscles straining to carry the box. Even Teyla's tablet looked kind of heavy, and since Rodney was having trouble holding himself up, he didn't want to think about how hard it must be for them. No one was complaining though and Teyla even kept giving him encouraging nods. It wasn't helping much. Especially since it was his mess they were having to clean up.

"I think I have to stop again," he said, tensing a little as Sheppard squeezed his arm before letting go. Rodney would have been embarrassed at the way he half-fell against the wall now that he didn't have someone holding him up, except that Ronon dropped the box with a relieved grunt and Teyla put the tablet on the floor, staying crouched as she shed her jacket. "Are you still getting messages from Jeannie?" he asked, already knowing the answer. They were so close now that they should have had their eight hour check in if it was coming.

Teyla shook her head. "There is nothing."

"We're too close. This could be worse than I thought." Sliding down the wall so that he was sitting on the floor, Rodney gestured for Teyla to push the tablet across. The sensors in it couldn't read the time dilation, but it could give them some basic gravitational information.

All the graphs were in the red.

"What does that mean?" Sheppard slid down the wall to sit next to him, pulling at the zip on his tac vest and struggling out of it.

"Good plan," Rodney said, looking round at Ronon. "What would also be a good plan would be for you to leave most of your knives here, or you're going to end up dicing us all when we get to the ZPM room. Magnetism's a pain in the neck. Possibly literally."

Despite his unimpressed glare, Ronon started pulling knives from the usual unlikely places, and Rodney turned back to the tablet.

Sheppard nudged him. "How bad is it going to be in there?"

"Looking at this? Not quite black hole bad, but the magnetic and gravitational forces are all screwed up."

"Is that a technical term?"

"While normally I'd appreciate the sarcasm, I'm serious. The ZPM isn't acting like a black hole, or at least not like one I've ever seen."

"You can see black holes?" Ronon actually sounded genuinely interested, and usually Rodney would have taken the opportunity to explain. For now, he just glared.

"Whatever. Look, what I'm saying is that we're dealing with both gravitational and electromagnetic forces like nothing we've ever encountered. I can't predict what's going to happen in there. For all I know, we could all just be sucked straight into it, or we could all end up with our own local gravitational fields and times or it could look like nothing's happened. I just don't know."

There was a moment of silence, and Rodney found himself counting down in his head, trying not to think about how much time was passing in the control room. It could be days by now; Jeannie would be worried sick.

Sheppard's shoulder bumped against his again. "Then we'll figure it out when we get there," he said, with some of his usual, infuriating certainty whenever Rodney said he didn't know something. "Come on."

*****

BEFORE

They moved the argument to the conference room, since most people disapproved of shouting in the control room. Personally, Rodney didn't much care, but Woolsey definitely looked more comfortable sitting at his huge shiny table, his hands folded and brow furrowed.

"Doctor McKay, I'm going to have to ask you to explain yourself further," he said, with what Rodney felt was unnecessary calmness. This was big, even for Atlantis, and the least Woolsey could do was look a little panicked.

He closed his eyes for a moment, trying to think how to explain this in words of one syllable while working on a solution at the same time. And even if he was out of practice, that didn't excuse Jeannie getting there first.

"Somehow, we've got a time dilation field on Atlantis."

"I hate those," Sheppard said, with the fervor he normally reserved for Iratus bugs and losing to Rodney at video golf.

There was a slightly surprised pause, in which Rodney could almost hear the odd look Jeannie was giving Sheppard then she went on, "Something is causing time to run more slowly in one part of the city than in the others. Given what we've seen, I'd have to guess that it's something to do with the ZPM."

"Well, that's a brilliant leap of logic," Rodney said, opening his eyes and scowling right back when she glared at him. "Seriously, that's right up there with two plus two equaling four. Of course it's to do with the ZPM, which is something I figured out around the time that Zelenka told us it was the ZPM. Right now, the question is how did it happen and how do we stop it again?" Apparently Jeannie didn't have the monopoly on stupid questions today, although no one called him on it. Rodney was almost disappointed.

Everyone looked up as the conference room doors swung open and Zelenka hurried in, his hair sticking up worse than usual. Judging from the color in his cheeks, he'd run all the way from the ZPM room, and he looked around wildly for a moment before his gaze settled on Rodney.

Rodney's stomach sank, even before Zelenka said, "Rodney. The south pier"

"What in particular on the south pier?" Woolsey asked, but Rodney just shook his head, trying to think.

"It can't be. We checked that about a hundred times. Sam checked it. There's no way-"

"Well, it did," Zelenka said, his expression tense. "I double-checked the logs."

"The compensators were supposed to-"

"They didn't."

Woolsey got to his feet. "Could someone please explain to me what is going on?"

"In a minute," Rodney said, trying to wave him off, but he could see Sheppard frowning, and with Jeannie already opening her mouth to ask, he and Zelenka were out-numbered. "Fine," he said, standing as well. "But I'm going to have to yell in the control room, if no one minds too much."

It took him a few minutes to pull up a schematic of the city, and another thirty seconds to convince the sensors to just display yesterday's data. They were having trouble with current readings, which meant that at least some of the time dilation had to have reached the main array by now. Adding to his list of things to compensate for, Rodney turned to the assembled audience.

"Okay, Ancient engineering 101. The city's main systems run on ZPM power. That's what they're designed for. Our Naquadah generators can compensate and take some or all of the strain, but they can't achieve the ZPM's level of efficiency. About two months ago, we received an experimental Naquadria generator from Earth, which in theory should have been twice as powerful as a Naquadah one, but when we hooked it into the city's systems, we only got about twenty-five percent above what we were getting from Naquadah. Everyone with me so far?"

"Naquadria fail, we got it," Sheppard said, and Rodney shook his head.

"Not entirely. The one thing the Naquadria was good enough for was hooking straight into the ZPM power conduits, channeling its power through the ZPM directly."

"We couldn't do that with the Naquadah generators?" Woolsey was squinting at the map of the city, with its dots of color: yellow for the Naquadah generators, green for the Naquadria one.

"Not powerful enough," Zelenka told him. "The conduits require a certain level of voltage which is proportional to-"

"Look," Rodney interrupted, because they seemed to be getting off the point, "it doesn't matter why, okay? We were using the Naquadria generator to feed power through the ZPM. There's a distribution station down on the south pier that we used to hook it into the system. That's the whole story and it was working fine."

"Until it wasn't any more."

While Rodney wouldn't have put it quite like that, he had to concede that Sheppard had a point. "We were adjusting some of the transfer levels about, what?" He turned to Zelenka. "Six weeks ago?"

Shifting a little awkwardly, Zelenka glanced at Jeannie then said, "More like four. Just before.."

Right. Rodney remembered vaguely that he'd been trying to construct some kind of regulator between Atlantis' systems and the power compensation protocols that Sam had built into the generator. The memory of having the idea was still clear, but the details were a little hazy. Which might at least explain why things had gone wrong. While he'd always known he was indispensable, it was a little disconcerting to be presented with the proof. And wait just a second...

He turned to Zelenka, who took half a step backwards. "You let me work on this when I was sick?" It came out as a question, but it needn't have.

"I double-checked all your calculations!" Zelenka protested, his eyes darting from side to side as though someone was going to come to his defense. "You couldn't remember all the details but you got through most of it."

"Well obviously not enough! What the hell were you all thinking, letting me do that? Actually, don't answer that." He didn't meet anyone's eyes, keeping his gaze on the floor and trying to think. "Are the plans in the database?"

"Yes, of course."

"Then pull them up for me." Rodney shooed Zelenka towards a computer, trying to ignore the way he could feel everyone looking at him. It was making his head hurt. "I get it. I was sick, everyone was very sad, but at what point did the insanity become infectious?"

"Mer, that's enough."

The whip-crack of Jeannie's voice was enough to startle him into looking up, and he looked away again quickly when he saw the look on her face. Behind her, his team's expressions ranged from the disapproving to the downright uncomfortable, and Rodney felt on safer territory with Woolsey, who was regarding him with a mixture of impatience and tolerance. Rodney got that a lot.

"Look," he said slowly, turning back to Jeannie without actually looking at her, "I'm just saying that it was somewhat irresponsible of everyone to let me take part in projects when they knew I was ... " He waved his arms vaguely, searching for the word. " ... not quite myself," he managed, a little startled when she reached out and gripped his flailing hand.

"Radek said he double-checked your work."

"Well he obviously didn't check it carefully enough, because now, we're going to have to go down there and see what's actually wrong with it."

Sheppard gave him a skeptical look. "Are you sure you're up to a field trip?"

"No," Rodney said automatically, "especially since the transporters are out so we're going to have to get all the way down to the south pier on foot. But I designed the regulator. I seriously doubt that anyone else is going to be able to fix it in time."

"I thought we had plenty of time." Tilting his head a little, Sheppard frowned. "You said time was moving more slowly down in the ZPM room. Doesn't that give us more time to fix whatever went wrong?"

If Rodney had wanted to teach Physics for Dummies, he would have taken that post at MIT. At least that would have come with a decent salary and lack of weekly peril. "Time is relative," he said, as slowly as he could bear. Sheppard might have been inside a time dilation field, but apparently Rodney's subsequent explanations hadn't really sunk in. "It appears slow to us from the outside, but in the ZPM room, it'll feel like it's passing at normal speed, which means it could reach the point of no return before we get there, even if we go as fast as we can. And once we're inside the time dilation field, time will slow for us as well, and depending on what's happened, we could be experiencing time more slowly or even more quickly than at ground zero." Since Sheppard's eyes seemed to be about to cross with the effort of understanding, Rodney gave up, starting to look round for the emergency tool kit that he was bound to need. "Just...take my word for it, okay? We need to hurry."

*****

NOW

Ronon was the next to call a halt, which startled Rodney enough that he almost didn't stop. He turned just in time to see Ronon drop the box with a frighteningly loud thud, then stretch out his arms with obvious pain. A quick mental re-orientation confirmed Rodney's suspicions; they were right over the ZPM room.

"Do you really need everything in here?" Sheppard asked, bent almost double as he tried to catch his breath.

"I don't know!" Rodney tried not to let his knees buckle, despite the overwhelming urge to just sit down and rest. If they hadn't had to traipse all the way out to the end of the south pier on foot, maybe they would have had enough energy for this last run. As it was, he was starting to think that being sucked into a black hole would be a mercy. "There's no way of knowing."

"Look, you said yourself that metal was a problem." Oh good grief, Sheppard was trying to be reasonable at him. "Aren't most of these things metal?"

"No, because I'm not an idiot! And the one that is - especially the regulator that I'm sure everyone remembers so very well - is absolutely essential to what we're doing here."

"If you don't know what you need, how do you know that?"

"Alright, that's it." Putting his hands on his hips, Rodney summoned up as much dignity as a winded man with a head injury could muster. "If any of you think I don't know what I'm doing, just say so now."

"That is not what we are saying, Rodney." Teyla held up a hand, but Rodney was in no mood to be placated.

"Yeah, but it's what you've been thinking, right from the start of this, and don't tell me you haven't. Look, I know I was sick, okay?" he said, gathering too much momentum to stop. "And I know that everyone's trying really hard not to say it or ask it or anything like that, and I know what I said earlier, but I am better. I know my name, I know where I am and if you're not careful I'm going to start reciting pi to as many decimals as I can damn well remember so either say what you're thinking or give me a break."

The others looked at him for a long moment, then Ronon crouched in front of the box. "So you just need the regulator then?"

Sheppard was still leaning over, his hands on his knees to keep him from falling, but he turned his face towards Rodney, quirking his eyebrow just enough that Rodney felt some of the anger drain out of him. Because it was the same way Sheppard always looked at him, always and yes, okay, it was possible at this point that he was projecting, just a little, what with the panic and the speed that everything had seemed to happen at and the fact that it felt like forever since anyone had asked him to use his brain like this. He'd said he was feeling a bit rusty. Maybe he needed to give himself a break.

Weakly, he said, "Just the regulator and the crystals should be enough, yes. The metal in our clothes is going to make this harder work, but unless anyone fancies doing this naked-"

Sheppard swallowed a grin. "No."

"No," Ronon said quickly, passing a pile of crystals to Sheppard. Teyla laughed - actually laughed - and held out her hands to take more of them, then they were all on their feet and moving again, Sheppard grabbing Rodney's arm as they reached the top of the last flight of stairs.

"Ready?" he asked, still with his eyebrow half-raised and that odd quirk of a smile on his face. That wasn't his 'we're going to die doing the right thing' face. That was his 'I'm so going to call you on that when we get out of this' face.

Rodney nodded. "Ready."

*****

BEFORE

Rodney wasn't entirely surprised to have Ronon and Teyla tag along as he and Sheppard started out for the south pier. The hazy memories he had of the past month featured them lurking in the background or hovering around him, mostly silent but always there, in the same way that Sheppard had always been there. Running down the stairs, with Sheppard at his elbow and Ronon and Teyla behind gave him an odd sense of deja vu.

He couldn't really spare the breath to talk, but that had never stopped him before. "Jeannie and Radek are going to see if they can configure the computers to transmit signals despite the time difference. Since we don't have a particle accelerator handy, we can't get the power to move nearly fast enough for instant transmission, but we might be able to convince Atlantis' systems to compensate for gravitational anomalies and at least pass the message on, even if it's not in a timely fashion."

"Which means?" Ronon asked, raising his voice to be heard over the sound of their boots pounding down the stairs.

Rolling his eyes would probably have meant taking the quick and painful way down, so Rodney settled for biting sarcasm. "They're going to convince the computers to work despite the time problems."

"Why didn't you say that?" Sheppard hesitated at the bottom of the stairs. While Rodney wouldn't have trusted him to find his way out of an alien paper bag, Sheppard usually knew the quickest way to get around Atlantis, even if it didn't seem the most obvious route. "This way."

About halfway there, Rodney really, really wished he'd taken the time to see if the transporters could be fixed. His lungs were burning and his head was spinning, but Sheppard didn't seem inclined to let up on the pace. While Rodney was definitely in favor of people taking his dire warnings seriously, maybe next time he should go easy on the galaxy in peril overtones. First Teyla, then Ronon drew alongside him, giving him what were probably supposed to be encouraging looks. He appreciated the thought, even if he was started to fantasize about wheeled vehicles that would fit down Atlantis' hallways. Maybe a super-charged go-kart.

"Where exactly on the pier is the generator?" Sheppard asked, barely breaking his stride as he looked over his shoulder.

Rodney was forced to slow a little to get enough air to speak. "Down by the grounding station."

"Of course. Because anywhere closer would make this too easy." To Rodney's horror, Sheppard actually sped up. At this rate, it really wasn't going to matter when they reached the generator, because Rodney was going to be dead of a heart attack before he got there. "You okay?" Sheppard asked, his capacity for stupid questions apparently not inhibited by the exercise.

"Assuming my brain doesn't explode out of my skull, I'm fine."

"Nah." Sheppard shot him a grin before upping the pace. Again. "It did that last week."

*****

NOW

This close to the ZPM, Rodney imagined that he could feel the gravity pulling on time, pulling at all of them as they staggered towards it.

"So how long is this going to take off my life?" Sheppard asked, leaning on the wall outside the ZPM room.

"Nothing," Rodney said, shaking his head and gesturing for Ronon to pass him the regulator. It was warm and far too heavy for his liking. "Time's moving slowly down here, relative to the rest of the galaxy. We're going to gain time, if anything. A day or two, maybe. Possibly a week if things are worse than we think."
"Perhaps we should harness it as a weapon against the Wraith."

Caught off-guard, Rodney turned to Teyla more with surprise than anything else. She raised an eyebrow, still half-smiling at him and he snorted with laughter.

"Yeah. Just as soon as I find a way to stop it sucking the room, the city, the planet and probably the solar system into oblivion."

"That would be most useful Rodney, thank you."

Everyone's smiles disappeared as the floor beneath them shook, and Sheppard gave Rodney a grim nod. "Any time you're ready."

He really, really wasn't ready for this. His head hurt, a sharp pain over the scar on his forehead and a dull ache through the rest of his skull. He was out of breath, hot, uncomfortable and would have quite liked to just lie down and sleep at this point, if nobody minded too much. The trouble was, of course, that they did mind, and they were all watching him expectantly.

"Right," he said, and waved his hand over the door control.

*****

BEFORE

The Naquadria generator looked surprisingly benign. Okay, so every panel on every wall of the room around it was glowing or flashing or sounding alarms, but the generator itself wasn't giving off radiation that Rodney could detect, nor did it show any signs of imminent explosion. Or implosion for that matter. It was just sitting there, plugged into the wall, a gray, impassive lump that was just reflecting the crazy light show around it.

"Well, that's a let down," Sheppard said, leaning against the wall, his chest heaving. Rodney tried not to be too pleased about that.

"We knew the ZPM was the source of the problem," he said, holding up the scanner. "But all of this," he waved a hand at the displays, "suggests that the source of the ZPM's problem is here. Pass me a screwdriver, would you?"

Ronon rummaged in the toolkit that Rodney had thrown together. "What size?"

"The littlest." The hard slap of the tool made Rodney jump a little, but his mind had already moved on to other things. The generator's output was cyclical, to try to allow for the instability of the Naquadria. Sam's compensators took the edge of the worst of the surges, but Atlantis' systems had still protested until Rodney had constructed the regulator. Looking at the readings he was getting, that was going badly wrong.

"Okay," he said, running the tip of the screwdriver down the main power lead. "Let's see what's going on here."

Ronon and Sheppard moved one of the Earth cabinets out of the way, letting Rodney and Teyla pull off a wall panel.

"The regulator's like a kind of intelligent capacitor," he told her as they both tried to look through the hole at the same time. "It can store the irregular charge from the generator and release it steadily into the city's systems. But it can switch itself off if the generator goes through a low power cycle, or if it goes through a high one. Better it just releases all the power than we blow up a Naquadria generator."

Teyla tilted her head, her hair brushing against the side of his neck in the tight space. "But would that not mean that the overload would be transferred into Atlantis' systems?"

"Yeah, a little," Rodney admitted. "But all the systems have surge protectors in them, and in an absolute emergency, the city automatically diverts the power to the grounding station. Huh."

"Is that a good huh or bad huh?" Sheppard asked, his voice way too close

"Can't you tell?" When Rodney glanced over his shoulder, Sheppard was leaning down, peering into the hole as though he had a hope of understanding the tangle of wires and cables inside.

"Rodney," he said warningly.

"Fine." Rodney sat back on his heels, wondering it would be a good or bad idea to rub at his eyes. It probably wouldn't help his headache, so he settled for running a hand over his sweaty forehead and trying to think. "As far as I can see, the regulator's working fine, the power was flowing through fine, everything was fine."

One of the louder alarms chose that moment to let out a particularly obnoxious sound. Ronon strode over the panel, looking as though he wanted to shoot it, finally just slamming a button with the heel of his hand, and the siren cut out.

"Fine," he said, turning back to Rodney with a deeply unimpressed look.

"You think?" Sheppard straightened up. "So if the generator's fine, the regulator's fine and the power is fine, what-"

"The power." The idea wasn't more than a vague thought as Rodney scrambled to his feet and half-ran to the generator display screen. "Teyla, how many of those conduits have actually got power flowing through them?"

There was a slight pause, and he took advantage of it to switch the display, going over the charts for the past month. It had to be here somewhere.

"All the conduits are active, Rodney," Teyla called.

"That's what I was afraid of." There it was. Four weeks ago, just after they'd fitted the re-programmed regulator. A long, low dip in the power outflow. Damn Sam and her 'I've compensated for that' reassurances. And damn him for not thinking of this before they plugged it into the city. "Okay," he said slowly, turning to the others, "I think I know what happened."

Sheppard tilted his head a little, maybe puzzled, maybe hopeful. "Can you fix it?"

"Maybe." Glancing back at the screen, Rodney tried not to frown. It made his forehead hurt.

"Only maybe? Rodney. Rodney!" Sheppard waited until Rodney turned back to him before asking again, "Only maybe?"

"I don't know." He could see it all in his mind's eye, the series of events, the chain reaction from the generator to the ZPM, but reversing that chain reaction? That was a whole other thing.

"Perhaps we should ask Doctor Zelenka to come down and help," Teyla said softly. "Or perhaps Jeannie would-"

"They're safer up there," Rodney shot back, shaking his head. He just needed a minute to think. He could do this. He had to do this.

When he turned his head a little, Sheppard was right there. Apparently looming over Rodney's shoulder was a game he was never going to get tired of. He lowered his voice a little. "Look, Rodney, if you can't do this then you just need to say so. If we need evacuate the city, then we need to start now."

"There's nowhere to go," Rodney said, trying to match Sheppard's controlled tone. "We can't open a wormhole with unstable gravitational forces so nearby, as I think we just graphically demonstrated, and there aren't enough Jumpers to get everyone in. The Daedalus isn't due for three more days. Not to mention the fact that if we just run off and leave this, the whole city's going to be sucked into it, then the planet, then..." He trailed off, seeing the understanding dawn in Sheppard's eyes. "We have to fix this."

"So fix it."

Rodney hesitated. The idea lurking just behind his consciousness was completely insane, and almost certainly wouldn't work. On the other hand, that went for most of Sheppard's plans, and they'd yet to come out of any of those dead. On the third hand, if it didn't work, he would almost certainly make things worse. On the fourth hand, if he did, Jeannie and Zelenka would probably come up with a solution between them. Then again-

Rodney was running out of hands. Over-thinking wasn't something he was unfamiliar with, but this amount of second-guessing was going to drive him nuts and possibly get them all killed if he didn't get a grip on it.

Pulling himself back to the present, he found Sheppard still watching him, still waiting for his answer. "I think I can fix it," he found himself saying. "Just let me think for a second, okay?"

"Is it supposed to be doing this?" On the other side of the room, Ronon was staring at one of the display screens, which was flashing out of sync with the other monitors.

Rodney hurried over, blinking in surprise. "It's Jeannie. They must have found a way to get communications through." He flipped one of the switches and ran his eyes down the lines of text. "Okay, the dilation field is expanding at a steady rate, as near as they can tell from the few working sensors. It's moving slowly, slower than a black hole would but the gravitational forces at the epicenter are already starting to destabilize. If it gets much worse, we could end up with a real black hole at the center of Atlantis."

"I thought that is what had already happened," Teyla said, brushing dust from her hands as she came to join them.

Rodney shook his head. "It's not quite like that."

"Then what is it like?" Ronon asked, and Rodney was about to dismiss the question when he noticed the way Sheppard and Teyla were giving him equally quizzical looks. He didn't have time for this, but he couldn't think properly with them staring at him like that. Maybe if he could break the problem down, take it right back to where it started, something would occur to him. Something usually occurred to him. And if it didn't, something usually occurred to his team, assuming he could make them understand.

"Alright, fine," he said, fishing in an inside pocket and looking round for a bare patch of wall. "You're about to get a crash course in the theory of relativity. Everybody ready?"

The wall above the panel they'd removed was smooth and gray. Perfect. Rodney finally got hold of his pen and pulled the lid off, only then becoming aware of the look Sheppard was giving him. "What?"

"Do you always carry a Sharpie with you?"

"Yes. So?"

"Never mind." Sheppard shook his head. "Relativity."

Trying to get his train of thought back together, Rodney started writing. "Okay. E=mc2 right?"

"If you say so." Ronon rumbled, and Rodney spared enough of his attention to glare at him.

"You know, this is going to go a lot quicker without the heckling. E is energy, m is mass and c is the speed of light. Basically what it's saying is that energy and mass are related. More than related. They're interchangeable. Mathematically speaking. What we've got with the ZPM," he drew a basic diagram of the crystal structure next to the equation, "is something that can draw on huge amounts of energy - technically infinite amounts of energy - and turn it into usable power. What we did was hook our generator into its conversion circuits," he drew a box to represent the Naquadria generator, linking it to the ZPM with two thick lines, "so that it could use the power from the Naquadria as well. The regulator was supposed to protect the system from power surges, because the one thing we know about Naquadria is that it's highly unstable. What no one seems to have thought of-"

"Including you," Sheppard interrupted.

"Did I not mention the heckling? No one spotted that unstable doesn't just mean it sometimes puts out too much power. About four weeks ago, it went through a long phase of not putting out enough power, so that the regulator effectively switched itself off." He bent to peer into the open panel again, double checking the conduits and making adjustments as he spoke. "Which would have been fine, except that the ZPM's systems had been reprogrammed to expect the power from the generator at a certain level. When it didn't arrive, the city's AI went looking for it, and found that the generator wasn't giving off enough power, probably because too much of the Naquadria had decayed into Naquadah."

"Are you even getting close to the answer?" Sheppard asked, folding his arms. "'Cause I'm fairly sure you said something about a black hole a while back."

"Oh, I'm sorry if my hugely complex feat of engineering can't be written on the back of a postage stamp for you, Colonel," Rodney snapped, trying not to bang his head on the edge of the panel as he stood up. "This is complicated, alright?" He started to scribble more equations on the wall, because he was close to an answer, he could feel it.

"Fine," Sheppard snapped back, matching his irritable tone, "but you don't seem to be getting close to telling us what you're going to do about it."

Which, although Rodney would bite his tongue before admitting it, was a fair point. The problem itself was fascinating; he'd never thought that the ZPM could do this, and the possibilities not only for his field, but for engineering and chemistry were potentially limitless.

"Well," he said, turning and putting the cap back on his pen, "somehow I thought that if I just said that the ZPM was trying to reverse the laws of physics and broke spacetime doing it, you'd tell me I was dumbing it down too far."

"McKay," Sheppard growled.

"I meant that literally. The ZPM is trying to convert the Naquadah back into Naquadria. It's already set up to feed power back into its own systems if it doesn't get used, and it's supposed to repair what it can automatically. When we messed with the base code to let it accept power from the Naquadria, we must have somehow made it think that it should attempt to put things right if they went wrong, and that if it poured enough power back towards the generator, it could somehow convert the Naquadria back. Which can't be done, or at least I don't think it can. But it's using tremendous amounts of energy trying, which is building up in the circuits, hence the blow-out. And since it's drawing on vacuum energy, with is theoretically infinite, it's got a lot of energy at its disposal. The only drawback is that the energy has to be channeled, turned into a usable form through the crystal structure of the ZPM itself. And the structure can't handle the energy it's using."

Teyla was nodding slowly, staring at the equation behind Rodney's right shoulder. "And that is why the time dilation is occurring. Because of the excess energy."

"Exactly." Seeing that Sheppard and Ronon weren't quite on the same page yet, Rodney tapped his pen against the wall. "Energy and mass, remember? All that energy has mass. And at the levels we're talking about, it's got potentially infinite mass. That warps gravity, which warps time."

"So how do we stop it?" Sheppard asked, glancing from Teyla to Rodney and back again.

"Can you mess with the base code again to stop doing the thing with the generator?" Ronon asked, and Rodney blinked because, yes, okay, that was a really sensible question and had pretty much been where he was going.

"Possibly. If we just disconnect it, all that energy's got to go somewhere and best case scenario? The resulting explosion turns this planet into a neutron star."

"Which would be bad," Sheppard put in.

"Very." Rodney's mind was racing so fast that he almost felt giddy. The flow of ideas felt so good, a heady rush of inspiration and deductions falling over each other, tumbling into place in that perfect, harmonious order that only came with really good math. It was the best kind of high, and he could have lost himself to it if it hadn't been for the way the others were still looking at him expectantly. "We need to find a way to bleed the power off without blowing anything up, as well as stopping the ZPM from drawing down more."

Sheppard was scratching his cheek thoughtfully. "What about the grounding stations? Could they handle the discharge?"

"Most of it." Rodney uncapped his pen again and began writing numbers on the wall. "Yeah. I mean, the city's still going to get a bit fried, but nowhere near as badly as it would do otherwise. We can probably channel about, what? Eighty-five percent of the power through the grounding stations. That's still a hell of a bang, but it's better." He snapped his fingers at Ronon. "Send a message back to Jeannie and Radek. Tell them to start re-routing all the city's power systems. I want everything possible shut down and everything else to go via a grounding station ready for the surge."

"Got it."

As Ronon loped off, Rodney turned to Teyla. "We're going to need spare crystals. Lots of them. Cannibalize all the adjoining rooms, everything you can see. We're going to need it all."

"Of course."

Rodney was already double-checking his math, the numbers and letters scrawled on the wall starting to fall into the order he was searching for. He waved Sheppard over. "Check this for me."

"I thought it would take too long for you to explain it all to me," Sheppard drawled, coming over anyway and running his eyes over the wall.

"It would." Rodney lowered his voice a little. "Just make sure I don't make four minus three equal twelve, okay? Let me worry about the complicated bits." He shook his head when Sheppard gave him a startled look, turning his attention back to the wall and feeling his face burning. This was not something he would ever admit admitting to, not even to himself, but even he knew that this was bigger than him right now. "It's possible that I'm a little," he cleared his throat, trying to find the right words, "out of practice. It's been a while, you know?"

"Keller said..."

"She also drilled a hole in my head. Anything could have gone wrong." Everyone could accuse him of being a hypochondriac if they wanted, but it wasn't like these things didn't actually happen to him. Anyone would be a little freaked out, wouldn't they? "Just check the arithmetic, would you? Maybe Jeannie should have come down with us after all." He was aware of Sheppard staring at him for a long moment before turning his attention to the numbers. There wouldn't be any mistakes. Rodney didn't make mistakes, not with this kind of thing. Unintended consequences were a whole other thing, but mistakes with math? That didn't happen. Or at least, it didn't used to happen. But his mind hadn't been his own for a while now. Who knew what could have happened to him? Just because everything felt right, didn't mean it was.

By the time Ronon came back over, Rodney had reached the end of his calculations. Sheppard was still puzzling his way through the earlier ones.

"No reply yet," Ronon said, giving Sheppard - who was counting something on his fingers - a curious look.

"Don't worry, Colonel, you can take your boots and socks off if you want," Rodney said, rolling his eyes. "And just because we've persuaded the computers to let us send messages, doesn't mean it'll be quick. We'll just have to trust that we'll get one in the end. Do you know how to download things to a tablet?" He took Ronon's silence for a 'yes'. "There's bound to be one around here somewhere. Pull the information from that computer onto a tablet. We'll take it with us so we can stay in touch with them."

"Right."

Ronon almost fell over Teyla as she came back into the room, her arms full of crystals of all shapes and sizes. "Will this be enough?" she asked, and Rodney looked them over.

"Should be. Put them in the toolkit then help me disconnect the regulator."

She nodded, then came to kneel opposite him. "What is Colonel Sheppard doing?" she asked, almost whispering, as though the question was embarrassing.

"Checking the math," Rodney said shortly, ignoring her obvious surprise. "Now, we need to bypass this before we can take it out, or we're going to get a hell of a shock."

"Rodney." Teyla put a hand on his as he went to split the cable. "Why is John checking your math?" He just shook his head, and as usual, she understood what he wasn't saying. "You seem quite yourself again, Rodney. You should not worry so much."

"Yeah, but if I didn't, who would?" He tried to laugh as he looked up, but the sound died as he saw her expression, frustration tempered with sympathy as she frowned at him.

"We were all very concerned about you, Rodney. We still are."

The intensity of her voice made him look away, because yes, he knew that already but hearing it out loud was ... weird, in ways he couldn't quite wrap his head around. Having Sheppard check the numbers was overkill, he knew, and the look in Teyla's eyes told him that she knew it too. They trusted him. Probably.

Whether they should or not was another matter. Still not sure what he was supposed to reply, Rodney settled for nodding brusquely, then turning his attention back to the cables. "Watch the regulator levels, would you?" he said, hoping she would hear the thank you that he couldn't bring himself to say.

They worked in silence for a few minutes, Ronon coming back with the tablet and plugging into the computer without a word. Sheppard eventually made his way to the end of the math, then he and Ronon transferred it onto the tablet and into the database. Rodney had it in his head, but a back-up couldn't hurt. He and Teyla finally got the regulator detached, and they put it into the toolkit along with the crystals.

When Rodney finally straightened up, his knees cracked and Sheppard raised an eyebrow at him.

"Getting old, McKay?"

"In this city right now? Who can tell?" This was why Rodney preferred math to words. There was none of the imprecision in numbers, none of this trying to get language around concepts that were too big for it. He could understand the equations of time dilation, but trying to explain it to the others in words they could understand made his head hurt. Of course, that could also just be the speed with which he'd stood up.

Sheppard was at his elbow again, and seriously, if he was going to keep appearing there, Rodney was going to walk round the city with his back to the wall from now on. His blood pressure was never going to take all the sudden shocks. Still, it was nice to have someone to steady him when he swayed, and with Ronon around he didn't have to carry the toolkit himself even if he did have to put up with blank, intimidating stares from time to time. Teyla opened the door and Sheppard steered Rodney towards it.

"Come on, buddy. Just a little half hour run and we're there."

"Assuming the run doesn't kill me," Rodney grumbled, breaking into a gentle jog. "I'm not going to be much use if I get there dead, you know."

But he sped up a little when Sheppard tugged at his arm, since it seemed to be that or dislocate his shoulder. Next time, he was definitely brining something with a motor.

Of course, if they didn't make it in time, there wasn't going to be a next time. Sighing with what little breath he had to spare, Rodney began to run.

Part Two