Steed, investigating a number of probable arson cases, is led to the hairdressing salon of Olive and Jacques Beronne. He asks Keel to let Carol investigate the salon, but after she enters, there is an explosion from within

Dr. Keel resuscitates Elaine Bateman, the owner of a ballroom dancing school who has narrowly survived a murder attempt by gassing. When he returns to the school after dropping his scarf, he is arrested. His scarf has been used to strangle the woman.

Classified information is finding its way into the wrong hands and Steed feels sure that this has something to do with the death of the magician's assistant at the club where Venus Smith is working. Steed investigates the lethal vanishing cabinet.