A mortal will destroy the primeus and free the souls—if she hasn’t lost her own first. Rome, 64 AD. Cassia, a young temple servant, knows who is guilty of the death of her friends. When a girl, who is immune to demonic forces, is given the chance to challenge her opponent—the great Janus—she agrees without hesitation. She must, as a slave, infiltrate his private quarters and steal one of the vessels in which he keeps souls. But all plans fall apart when Belial appears—a promising devil with an irresistible smile, and Janus’s main rival. Cassia doesn’t yet realize that she’s about to become the center of the most dangerous battle: the battle for her soul.