Book of a Thousand Days by Shannon Hale
Oooh! This one is good. Hale based this book on the Grimm fairy tale "Maid Maleen", but really came up with a story that felt new and vibrant. Dashti is maid to Lady Saren and finds on her first day of employment that she and Saren are to be locked in a tower for seven years. Dashti is a true and loyal servant, spending much of her time trying to make life bearable. She discovers as time goes on that her lady is mentally fragile and has been terrified by something that happened in her past. Dashti must use her own wits and fortitude for their very survival.
I really like this book. The prose was lyrical, the characters were fully dimensional, and the romance was convincing. YAY!