The police are called to the island's volcano observatory when head vulcanologist Stephen Langham is found dead, presumably of a heart attack though Goodman suspects foul play. The victim's brother, drug addict Daniel, his lover Victoria, who plagiarized his work and the mysterious Megan Colley, another colleague, are all in the frame though commissioner Patterson believes that shifty mayor Richards also had a row with the victim over a planning dispute. In fact there is more than one killer and, having named them, Humphrey can concentrate on entertaining visiting girl-friend Martha.