I've gone on record in Maggie's LJ to laud "OSON", so I won't repeat myself here .
But I thought I might use this thread to also recommend Maggie's latest entry, the canon one-shot "The Coven", which is in her LJ and isn't F-locked. The fic's short, and deceptively simple, and about as devastating and haunting a BBM fic as I've ever read. Do read it, if you haven't already - but be warned of the angst.