Henry Perkins accidentally picks up a wrong briefcase full of money. Henry assumes it is illicit cash and decides to keep it. Knowing that the former owner must have his briefcase, he rushes home to book one way fares to Barcelona.
The doorbell rings, the police thinks Henry was soliciting in the men's room of the local pub actually, he was sitting in the loo counting the cash. The door bell rings again. Another detective arrives thinking Henry is dead; a man with bullet holes in his head and Henry's briefcase were found in the Thames.
Henry's attempts to extricate himself from this impossible situation lead to increasingly hysterical situations.