Paul is in Rio de Janeiro trying to trick Larry Carter (Peter Lawford) into returning to the US to face trial when Molly Pierce (Anne Helm), daughter of his victim, makes an attempt on the murderer's life.

Paul is no longer aware of his diagnosis after a tobogganing accident brings on amnesia, so he returns to his fiancée Kate Pierce (Carol Lawrence) in San Francisco to help him with the mystery of six missing months in his life.

Paul experiences friendliness turning to malice when he is oppressed with demands from all sides after winning a fortune in the sweepstakes.

When Alex Ryder (Bruce Dern) availed of the opportunity to fake his death and collect substantial insurance money, his wife Molly (Anne Helm) turns to Paul for help.

A casual remark to Deputy Sheriff Potter (Warren Oates) in a small American town leads Paul facing a certain 15-year prison sentence.