Campion learns that a mediaeval relic called the Gyrth Chalice, which for hundreds of years has been in the care of the Gyrth family at the village of Sanctuary, is threatened by an international gang of art thieves. For the Gyrths the stakes are high - if they lose the Chalice, their country estate will revert to the Crown. Campion travels to Sanctuary with Val Gyrth, and almost at once Val's aunt Lady Diana is found dead in the middle of a wood, apparently frightened to death... it seems the gang is already on the job.

When the safety of the ancient Gyrth Chalice is threatened, Campion embarks on a dangerous assignment to protect it. He soon discovers that his adversary will stop at nothing - even murder - in order to get the Chalice.

A murderer is on the loose at Cambridge, where the family of the late Professor John Faraday is being murdered. His niece's husband Andrew is found in the river with a bullet in his head, then his daughter Julia is poisoned and his son William is attacked. Campion is called in by a friend, and Caroline Faraday, the Professor's widow, retains hin to protect her eccentric children William and Kitty and to find the murderer. Campion finds himself working on the case with Inspector Stanislaus Oates.

Campion receives a letter from an old Cambridge friend, asking him to help find a missing uncle of his fiancée. Campion is convinced that the murderer is part of the Faraday household.

'Pig' Peters dies and is buried... but then he turns up dead again...

Campion investigates the murder of 'Pig' Peters, whose funeral he attended three months earlier.

Campion is convinced that a third murder is imminent. The inquest into the death of Claire Potter reveals that she died from nicotine poisoning.