Cain Pseudomantis leads a miserable life. Bound to the mortal world by a powerful spell no demon could hope to break, he must obey his human master’s every command or face harsh punishment. He finds solace in the rock music which he listens to when he isn’t running unsavory errands for his master. Then everything changes. While on a mission in a seedy section of 1980s Los Angeles, Cain impulsively buys an electric guitar and discovers an unusual talent for music, a talent that catapults him to hair metal stardom. With three superpowered human band mates and his beautiful girlfriend Michelle by his side, his life starts to look a lot better. But Cain soon finds that even rock stars have troubles. The crusading televangelist Nathaniel Breen—who happens to be Michelle’s father—accuses him of turning the city’s youth to Satan worship. Meanwhile a mysterious killer known only as the Engineer terrorizes the Los Angeles rock scene with a series of brutal murders. When Cain and his friends attempt to unmask the killer, they discover a deadly secret that could cost Cain his hard-won freedom, and possibly his life.