Nightshade By Andrea Cremer

Calla Tor has always known her destiny: After graduating from the Mountain School, she'll be the mate of sexy alpha wolf Ren Laroche and fight with him, side by side, ruling their pack and guarding sacred sites for the Keepers. But when she violates her masters' laws by saving a beautiful human boy out for a hike, Calla begins to question her fate, her existence, and the very essence of the world she has known. 

By following her heart, she might lose everything- including her own life. Is forbidden love worth the ultimate sacrifice?