Takes place shortly after Caleb's uncle is killed, when Ben's dragoons make it back to camp. AU in the sense that here Ben already knows about the supernatural, which in the official timeline doesn't happen until sometime in S2.
Caleb barrages into Ben's place, enraged and shouting. "I knew it! I was right all along, Simcoe is a thrice-damned bastard son of a-"
"Caleb, slow down, what is going on?" Ben springs out of his seat when he sees how worked up Caleb is, ready to do damage control.
"I knew there was a reason I had that gut feeling and I should have listened to it! I should have ran Simcoe through back when I had the chance!"
"Not so loud, everyone will hear!" Ben doesn't want the story of how he treated an enemy officer in his care to get out to too many people. No matter that he had good reason to do so, he fears that others will only see him as a savage officer willing to dishonour and disregard the deals regarding prisoners’ treatment.
"Yeah, so? So what? I ain't ashamed of that! There ain't no shame in ridding the world of a monster!" Caleb agitatedly paces across the room.
Ben jumps a bit at the word, but after surrepetitiously checking their surroundings to make sure no one noticed, decides it's just the fact that he's still reeling from his relatively recent introduction to the supernatural world making him too cautious. Monsters can be human too.
"Alright, just tell me, what has brought this on? I thought you had already sworn to kill Simcoe next time you see him-"
Caleb interrupts him, laughing crudely. "Oh but that's the joke Benny. I can't. Don't you get it?"
Ben shakes his head. "Get what, Caleb, I don't..."
"I found sulphur on my uncle's body," Caleb states and waits for him to figure it out.
The words hang heavy in the air between them. To Ben, it feels as if the whole word shifted and left him stumbling, trying to catch his balance. Sulphur means demons, and close contact, and the last person in close contact with Lucas Brewster was... Simcoe.
"No," slips past his lips.
"Yes," counters Caleb. "Isn't this just briliant? We had him right under our noses - well, my nose, you had no idea about demons then - and I didn't notice anything? What kind of a hunter does that make me?"
"Don't blame yourself, Simcoe had fooled everyone-"
"But the best part - the best part," continues Caleb, as if Ben had not said a word, "is that it makes my uncle's death entirely my fault."
"No, Caleb, don’t talk like that!"
"Why ever not? It’s true." Caleb slumps over on a crate, shoulders hunched.
Ben resolutely marches towards him. "The only one at fault here is the demon. You didn’t kill your uncle, nor did you encourage it to kill him. You say you should have noticed Simcoe was possessed when we interrogated him-but why? We used nothing that would force the demon to reveal itself and with the real Simcoe being in the royal army, it must have been pretending, acting like a human, for a good while before."
Caleb grunts but doesn’t look convinced, staring at the ground. Ben grasps his shoulder, making him look up, and goes for the last straw.
"Besides, Simcoe might not even have been possessed then."
That catches Caleb’s attention. "What?"
"Think about it," presses Ben. "You told me demons are here to make people’s lives as miserable as they can, right? Enjoying death and mayhem, acting on their whims."
"So?"
"So what would a demon do between the Redcoats? What could be the long term plan? If it simply wanted to plunder and ravage, it would be easier to do it as a mercenary. The army requires discipline and any soldier’s actions inevitably get back to his superiors. It would have been limited in its doings."
Caleb inhales and holds his breath for a while, then exhales, shaking his head. "You’re right, Benny-boy, as always. Talking some sense into me." He stands as if to leave.
Ben has no intention of leaving his friend alone right now.
"Oi," he says with a smile, "where do you think you’re going?" He reaches under his desk. "I’ve got a bottle of Madeira here with your name on it." Ben’s been saving it for an emergency and the situation certainly qualifies.
Caleb hesitates and then takes the bottle. "To my uncle," he says.
"To Lucas Brewster," Ben echoes the cheer.
Between the two of them, the bottle doesn’t last long.