Malachi is the last of his kind-a magus who can communicate with the dead, and who relies on the help of spirits to keep his kingdom safe. When he's sent to investigate brutal murders in the isolated village of Stonehill Downs, he uncovers dangerous sorceries and unleashes a killer who strikes close to home. Avani is an outsider living on the Downs, one of the few survivors from the Sunken Islands. She has innate magics of her own, and when she discovers the mutilated bodies of the first victims, she enters into a reluctant alliance with Malachi that takes her far from home. But Mal is distracted by the suspicious death of his mentor and haunted by secrets from his past. And Avani discovers troubling truths about the magus through her visions. She could free Malachi, but first they must work together to save the kingdom from the lethal horror that has arisen.