London, 1883. The American only known as Z has made a new home in the great city. However, Z is not like other men. Since he was just a boy, he's had the ability to see ghosts. Though the gift frightened him at first, he soon learned to live with it, and more, start his own business as a ghost hunter, ridding haunted houses of their restless spirits. Fleeing a horrifying past in the States, Z crossed the pond with his silver loaded revolvers on his hips and Stetson hat on his head, determined to hunt and fight the supernatural.
When Scotland Yard Inspector Charles Grant approaches Z with a job, the case pits the ghost hunter against an ancient evil. Asmodeus is coming and he brings an army of demons with him. Now, Grant must find the murderer who spilled human blood to summon the King of Demons, while Z races to find the one object that can drive the evil back to Hell. But will Z's past catch up to him first?