Damon Richter thought he left the world of possessions, exorcisms, and evil behind until an old friend arrives with frightening information about his estranged daughter knowing that only his otherworldly skills can save her.

Detective Damien Seryph investigates a string of murders that connects to a group trying to bring forth the 4 King Demons of Hell. Damien's past connects him to those involved and will force him to become "The Demonologist".