The Ministry has been broken into by, it seems, an invisible man. A trail leads via inventor Quilby to the Eastern Drug Company, a front organisation run by Soviet intelligence. Meanwhile, the crack spies Elena and Alexandre Vazin are in town. But nobody has seen anything of Alexandre....

Various millionaires are withdrawing large sums of money from the bank. Steed suspects blackmail but none of the men is willing to talk. Then he gets a call from Gilbert Jarvis, who tells Steed that he, Jarvis, has 'just been murdered'. Again.

Emma's old friend, Paul Croft, returns from abroad to retire to Little Storping-in-the Swurf. Unfortunately, the village seems to be run along very strange lines. Threatened by yokels, Emma finds herself outnumbered.