Alastair, Pete, Charlie, and Rachel aren't just magical teen detectives in their coastal town of Port Howl--they are also members of a local teen rock band. Before a show one night, Charlie and Rachel meet a famous rockstar, Gideon, and invite him to their show. He'll never come, but why not try, right? Little do they know, Gideon does show up, and he brings the threads of his dark past with him. In fact, he might even be the source of the rumored Devil's Music, a limited-release song that entrances all of its listeners in a deadly hypnosis. When Pete quickly gets drawn into Gideon's web, it's up to his brother and friends to save him. But Pete might not be the only Montague Twin at risk for Gideon's spell.