The series starred Peter Davison as Albert Campion, Brian Glover as his manservant Magersfontein Lugg and Andrew Burt as his policeman friend Stanislaus Oates.

Campion is called in by a friend, and Caroline Faraday, the Professor's widow, retains him to protect her eccentric children William and Kitty and to find the murderer.

Campion visits the country house of the famous dancer Jimmy Sutane to investigate a string of unpleasant practical jokes, and falls in love.

Campion is determined to prove the innocence of his friend Mike Barnabas, arrested for the murder of Paul Brande, but in trying to do so he puts his own life in jeopardy.

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.

Judge Lobbett mysteriously disappears, Biddy Pagett is kidnapped, and Lugg tries to warn Campion off the Simister mob investigation, but he refuses to give in.