Number Six is not himself. The Prisoner's mind is transformed in another man's body by The Village authorities in an attempt to track down a scientist, Professor Seltzman. When he awakes in his London home he has a tough task convincing people of his true identity, so he sets off for Austria to find Professor Seltzman - the only man who can help him.

The Prisoner is back in his old job as he tries to track down the murderer of Colonel Hawke-Englishe, who was looking for a crazy scientist called Schnipps. The scientist's daughter Sonia, who calls herself Death, protects her father and sets many deadly traps for Number Six. Sonia eventually leads him to her father who has plans to destroy London with his super-rocket.