This is probably one of those stories that got recced everywhere back in the day. It's so good I wish I'd written it. Cucumberspy has a lovely, spare style, plus an ear for dialogue and an eye for detail. Season nine, AU, thank God.
There are warnings on the author's header. Heed them.
Summary: She thinks there's nothing anyone can take from her now.
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Telephones.
SPOILERS IN THE COMMENT THREADS.