Damien Blackwell, a demon slayer for hire, navigates the streets of Victorian London armed with his great-grandfather's sword and a relentless resolve. Battling infernal creatures that prey on the innocent, Damien is haunted by his lineage and tormented by questions of his self worth. When children begin to disappear and his investigations point to the powerful demon Noctherion the Blackvein, Damien finds himself entangled in a sinister plot that threatens to consume the world.

As he delves into ancient secrets and dark deceptions, Damien becomes an unwilling host. Will he gain control over the demon while risking his humanity. With the help of the skilled healer Vivian Ambrose, Damien must navigate this new, perilous reality, standing as the last line of defense against the darkness.