Gabriel Voltz, an immortal tracker of supernatural beings, juggles his life as a loner, sarcastic and seductive while dreaming of freeing himself from the invisible chains that bind him to a mysterious brotherhood. His life takes an unexpected turn when he takes in Astoria Melrose, a young bourgeois girl orphaned after the brutal murder of her parents. Curious and talkative, Astoria can't help but ask questions that often put her in delicate situations. At the same time, Gregory, a young man of faith, is forced to join forces with Gabriel and Astoria. Although he struggles to tolerate their eccentricities, he recognizes the need for their alliance to elucidate a series of mysterious murders that strike their community. Together, this unlikely trio must navigate a world filled with secrets and dangers, while exploring the limits of their friendship and loyalty.