Sean Lynch hunts monsters—specifically, vampires. He's been doing it for centuries, alongside his partner Vida Godwin, a werewolf who struggles with her monthly transformations. Together, they work for the Sisters of Mercy, a clandestine Catholic organization dedicated to protecting humanity from supernatural threats. But Lynch has a dark secret: he's a vampire himself, using an ancient alchemist's tincture to suppress his true nature as he hunts his own kind. When Edward Drake—the most dangerous vampire in Britain and Lynch's own brother—escapes from the monastery where he's been imprisoned for eighty-four years, old wounds are reopened and buried truths threaten to surface. Drake has only one thing on his mind: revenge against the brother who betrayed him and the woman who chose mortality over eternity. As bodies pile up and Drake's bite creates something new and terrifying, Lynch and Godwin race to stop him. But the monastery that once held Drake harbours secrets of its own, and something darker than vampires is stirring within its ancient walls. With the government taking an interest and the body count rising, Lynch must confront his brother one final time—before Drake's vengeance destroys everything Lynch has spent centuries protecting. In a world where monsters wear human faces and holy ground offers scant protection, some sins can never be forgiven.