After Mike's band, �The Fresh Hearts� plays at a gig, a man named Jake asks Elizabeth if he could become the band's manager. This offer excites the band, but Elizabeth thinks that Jake is a cheat and a fraud. At a rehearsal Jake asks Mike to play his drums to the special rhythm on a metronome, but the cleaner working in the room starts to act very strangely, and has to be taken outside to recover. Jake says it is their music that affected her, and arranges for music television producer Mike Harding to watch the band play that evening. Harding is impressed, and arranges for them to play live on television. Elizabeth discovers that Jake is actually Professor James Marsden, leader of a religious sect known as the Hearts of Sogguth. She persuades John of infiltrate the group, and he is initiated into them, but thinks they are harmless. Jake gives Mike the Heart of Sogguth drum to play, but warns him not to play the special rhythm. Elizabeth takes John to watch the Mike's band play at the disco, and they are introduced as the Hearts of Sogguth by Jake. Mike plays the drum to the special rhythm affecting everyone in the room except for Elizabeth. She jaunts onto the stage and stops Mike, but then finds that John is acting very strangely. Elizabeth jaunts back to the Lab, telling Tim that she thinks that John and Mike are under someone's control. (thetvdb.com)