Beautiful Darkness by Kami Garcia and Margaret Stohl

From GoodReads: 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.

The second book in the Caster Chronicles, Beautiful Darkness lived up to the standard set by the first book in this series.  Full of twists and turns, heart-wrenching emotion, and characters that you just fall for.  In this book, Stohl and Garcia take us for an emotional rollercoaster ride as Lena tries to deal with the loss of Macon and pushes herself away from Ethan.  There were scenes that made me want to cry with the characters.  This book was amazingly written and I look forward to the third installment in this series.