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.
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 visits the country house of the famous dancer Jimmy Sutane to investigate a string of unpleasant practical jokes, and falls in love. On Campion's first night at White Walls, another guest, Chloe Pye dies - though whether by accident, murder or suicide remains to be seen. Then there are more deaths, and Campion finds himself under pressure.
American Judge Crowdy Lobbett has suffered several attempts on his life and has decided to leave the United States and travel to England in the hope of finding a safe haven. The Lobbett family meet Campion on board their transatlantic liner, and the Judge's son Marlowe asks him to help with their problems. Campion takes the Lobbetts to the village of Mystery Mile, where he has friends, but the Simister gang is on the Judge's trail and he soon disappears, leaving Campion and the Lobbetts with a kidnapping to solve in a hurry.