Evil has returned to Rawne Barton - this time in the form of a malevolent chemistry teacher, Yoland, whose aim is to gain power by stealing souls. Pip and Tim, newly started at secondary school, manage to get Sebastian, the alchemist's son, into their class so that he can uncover Yoland's evil plans. But Yoland has help - not only in the form of a stunted familiar who is also pretending to be a schoolboy, but from a mysterious supply teacher - who turns out to be Malodor, the evil alchemist from Doctor Illuminatus. A truly nail-biting climax takes place at a nuclear power station, where Yoland seeks to harness immense power to his ultimate spell.