Nightshade by Andrea Cremer
Calla and Ren's destiny's have always been intertwined. At birth they were matched by the Keepers, and when they turn 18 they will be mated. Both alphas, they will then begin to form their own pack, patrolling the area to watch for and prevent an attack by the Searchers. Calla has always known this, but as Samhain, and her birthday, gets nearer she finds herself...restless. When she discovers an injured hiker while on patrol she starts down a path that will expose the deeply hidden history of the Guardians, Keepers and Searchers, and drive Calla away from everything she's ever known.
This novel was a refreshing twist on the werewolf theme. Though there are definite Twilight overtones, the heroine is much stronger and the plot is more thrilling. I stayed up late reading this book and absolutely cannot wait to continue reading this series!