Following the death of his fiancee Peggy at the hands of heroin smugglers, Dr David Keel vows to track down the killers and avenge his lost love. He is aided in his quest by a mysterious stranger, John Steed.

Emir Abdulla Akaba is visiting London for his annual medical, and Steed suspects an assassination attempt. Despite Steed assumming the guise of a chef, the Emir seems to have been poisoned while eating a meal.

The directors of the Capital Land and Development Company are being murdered and the only clues Steed and Tara have are a massive footprint and a red nose.