I'm looking for a story where a woman discovers that her neighbour/housemate/landlord is a dragon. I think they share a (possibly old?) house, but maybe it's an apartment-building. I think main-character knows about supernaturals -- possibly is something supernatural (vampire, reaper, psycic) or has connections with supernaturals.
Anyway, at one point our heroine discovers a dragon in the house, and naturally attacks it. They fight for a while, before the dragon morphs into that of the woman she shares the house with.