Beautiful Darkness by Kami Garcia and Margaret Stohl

Ethan Wate used to think of Gatlin, the small Southern town he had always called home, as a place where nothing ever changed. Then he met mysterious newcomer Lena Duchannes, who revealed a secret world that had been hidden in plain sight all along. A Gatlin that harbored ancient secrets beneath its moss-covered oaks and cracked sidewalks. A Gatlin where a curse has marked Lena's family of powerful Supernaturals for generations. A Gatlin where impossible, magical, life-altering events happen.

Sometimes life-ending.

Together they can face anything Gatlin throws at them, but after suffering a tragic loss, Lena starts to pull away, keeping secrets that test their relationship. And now that Ethan's eyes have been opened to the darker side of Gatlin, there's no going back. Haunted by strange visions only he can see, Ethan is pulled deeper into his town's tangled history and finds himself caught up in the dangerous network of underground passageways endlessly crisscrossing the South, where nothing is as it seems.

-Amazon product description

This sequel to Beautiful Creatures takes the story of Ethan and Lena, and the history of Lena's Caster family, to a whole new level. Wrought with mystery and suspense, Ethan must discover the reasons behind Lena's strange behavior before her Seventeenth Moon. Which, at that time, will mean the difference between Lena returning to him, or being lost to the Darkness forever.

I really enjoyed this book. Like it's predecessor, it's pretty lengthy, but once you're drawn into the story it's a hard one to put down. I'm really looking forward to book three.

-Sam