An unidentified corpse is discovered after foreign agent Willi Fehr has tried to dispose of him . A tattoo shows him to have been Arthur Peever and leads the avengers to the Terpsichorean Techniques dance school run by the formidable Lucille Banks where Emma goes undercover as an instructress and Steed poses as a client. Here they discover a plot to kill lonely, unattached punters and replace them with enemy agents, infiltrating the country.
—don @ minifie-1