Miles Cullen, played by Elliott Gould, is a timid and unfulfilled bank teller who is discontent with his mundane life. His routine is shaken up when a man dressed as Santa Claus, played by Christopher Plummer, enters the bank and holds it up. However, only Miles knows that the robbery is going to take place as he had overheard a conversation between Santa and his accomplice, and had tricked Santa into revealing his identity to him.
Realizing that he has a golden opportunity to change his life and become a wealthy man, Miles conceives a plan. He discreetly assists Santa in his robbery, but takes a portion of the stolen money for himself while leading the police to believe that Santa had taken all of it.
As his newfound wealth changes his life for the better, Miles believes that he is in the clear until he starts getting menacing phone calls from Santa who demands his share of the money. To make matters worse, a detective, played by John Candy, begins to investigate the robbery and questions Miles.
The Silent Partner is a 1978 Canadian heist film directed by Daryl Duke, which also starred Susannah York and Céline Lomez. It was acclaimed for its intelligent plot, strong performances, and suspenseful finale. The movie is based on a novel by Anders Bodelsen called "Thieves Falls Out".