Here's what I remember from a fantasy book I've read years ago:
There's this girl locked inside a dark room. As in, total darkness. And she doesn't remember how she got there in the first place (if I remember correctly). Sooo, there are creatures inside that room and she somehow befriended most of them. I'm not sure but I think a witch has been keeping her there.
Huuuge mental leap, and the girl turns out to be a shapeshifter (or is it an animagus?).
I remebered the excellence of how it was written because you can really feel what she felt like being all alone; with nothing to see, but hear only weird noises.