When sixteen-year-old Lilly arrives in Castello, she isn't impressed. A secluded town in the Italian mountains is not where she saw her last years of high school playing out. Divided for generations by a brutal clan-family war, the two halves of Castello are kept from destroying each other by the mysterious General, a leader determined to maintain order and 'purity' whatever the cost. Lilly falls in with the rebellious Liza, brooding Nico and sensitive Christian, and sparks begin to fly. But in a city where love can lead to ruin, Lilly isn't sure she can trust anyone -- not even herself. And then she accidentally breaks Castello's most important rule: when the General's men come to test your blood, you'd better not be anything more than human.