The story is a fantasy. Aly, the daughter of a spy and a warrior (both of whom are nobles), is kidnapped and sold as a slave to another noble family in a different land. Aly plots her escape but before she can enact her plans, fate intervenes in the form of a god. The trickster god (his name is very Greek-ish and I can't remember how to spell it right) makes a wager with her that will last just one summer; being a bold, smart girl, she accepts. Aly puts to use all she's learned from her warrior mother and spy father to keep the wager...and to keep alive.
The book is related to Pierce's earlier works, The Song of the Lioness quartet, which actually follows Aly's mother. So...there was a fair amount that zipped over my head, simply because I didn't know the backplot. I hate when that happens, but I admit, it's my own fault for not looking into the series more before I dived in.
Still, the story was well-written, interesting, fleshed-out characters and all in all a great YA read.