Book of a Thousand Days by Shannon Hale

Synopsis (from goodreads.com):

When Dashti, a maid, and Lady Saren, her mistress, are shut in a tower for seven years for Saren's refusal to marry a man she despises, the two prepare for a very long and dark imprisonment.
As food runs low and the days go from broiling hot to freezing cold, it is all Dashti can do to keep them fed and comfortable. But the arrival outside the tower of Saren's two suitors--one welcome, and the other decidedly less so--brings both hope and great danger, and Dashti must make the desperate choices of a girl whose life is worth more than she knows.
With Shannon Hale's lyrical language, this forgotten but classic fairy tale from the Brothers Grimm is reimagined and reset on the central Asian steppes; it is a completely unique retelling filled with adventure and romance, drama and disguise.

Jillian’s Review:

I know many people thought this book to be a really slow read, but I loved it from beginning to end—both times through. I love—LOVE—Dashti. I love that she’s strong, sensible, and positive. Even when locked in a tower with the sulky and unstable Lady Saren, Dashti manages to look on the bright side of things. “And here’s the bit that makes me tremble with delight—in our cellar there is a mountain of food! … Seven years’ worth. Such a thing I never imagined. Even though I can’t see the sky, it’s hard not to want to dance about, knowing that for seven years at least I won’t starve.”

After a couple of years and the loss of an enormous amount of food because of a rat infestation and a Lady who won’t stop gorging herself, Dashti is a little less lighthearted and somewhat bitter. However, she never lets it get the better of her. She pushes forward, believing it an honor or at least somewhere close to an honor to serve a Lady.

And then enters the dashing Khan Tegus. Ooh, I liked him from the start. He’s kind and thoughtful and appreciates Dashti for who she is. It probably helps that their first couple of encounters they don’t see more than each others' ankles (thanks to the fact that Dashti is still locked in a tower with a slightly insane Saren). I love how the story progresses and ends. Yay, a happy ending.

Hale has a great talent for describing every detail so that it’s vivid and bringing each character to life, with just the right twist of humor thrown in. I had the perfect quote from the book as an example, but I can’t find it now. I guess you’re just going to have to read it and find out for yourself how great this book is.