"Rising above the city of Collis is the holy Sanctum. And watching over its spires is Catrin, an orphan girl with unique skills--for she alone can spot the building's flaws in construction before they turn deadly. But when Catrin witnesses a murderer escaping the scene of his crime, she's pulled into a dangerous chain of events where the only certainty is that the killer will strike again. Assigned to investigate is the mysterious and brilliant Simon, whose insights into the mind of a predator are frighteningly accurate. As the grisly crimes continue, Catrin finds herself caught between killer and detective while hiding her own secret--a supernatural sight granted by the moon, destined to make her an outcast, and the only thing that might save her and those she loves from becoming the next victims ..."-- Publisher's website.