The police investigate the murder of a former professional footballer, Robert Nichols, who is found lying beside his car bludgeoned to death. He was on his way to meet his sister and was apparently replacing a flat tire when the attack occurred. The only thing taken was his very expensive watch. They manage to trace a passerby, Mike Jones, who initially denies having seen anything but eventually admits he was helping Nichols fix his flat. The police are naturally suspicious and believe Jones may have been the perpetrator. In checking into Nichols's background however, they learn he was a big-time gambler and owed well-known mobster Don Marsh a quarter of a million pounds. Jones obviously has good reason to lie since he saw who killed Nichols but the mobster has made it clear that his life is in danger if he testifies.