Company chairmen across the city are dropping dead, apparently through natural causes. Can Steed and Mrs Peel discover who is making a killing?

A man-eating plant from outer space lands in Middle England and takes several top horticulturalists as is prisoners in an effort to germinate the Earth. Fortunately for the Earth, Steed just happens to be a herbicidal maniac.

A mysterious Russian called Psev is arriving for a conference at which Steed and Mrs. Peel have been hired to act as the security guards. However, a man called Gordon Webster who is an exact double for Steed turns up and offers his services to Psev's entourage of four people, fooling Mrs. Peel in the process and agreeing to kill Steed. Though he is thwarted it turns out that Psev is also not exactly the man that everybody had expected him to be.

Steed has been having bad dreams involving Christmas trees and a man dressed as Santa Claus. At a party given by publisher and Dickens fan Brandon Storey, two telepathic spies attempt to read Steed's mind and make sense of the dream. However, the dream is echoed exactly by the events of the party, enabling Steed to spot the villains in advance and identify the dangerous Santa.