OK, this should be really easy, and I've tried keyword everything....but apparently my cross reference/keyword-fu is sadly lacking. (As is my PC, because I know I had this saved, but the HD borked itself)
Post Chosen, post NFA. Buffy buys the old Pratt house & starts fixing it up. She finds a vampire lurking in her shed, he's badly burned and non aggressive, so she takes him in & fixes him up. He has amnesia, so she let's him live in her basement & calls him 'Bob' because he can't remember his name.
Naturally it's Spike, who is eventually healed enough to be recognized (actually i think he called Dawn 'niblet' by accident and got found out)& him and Buffy go avert an apocalypse.
Any nice folk willing to point me in the right direction?