Taking an important witness from Hawaii to San Francisco by plane, Ironside discovers that a fellow passenger is a hitman. He has to find out who is trying to kill his witness before the plane lands; but there may be more than one person trying to claim the reward for an open contract.

An apparently impossible robbery occurs in the safety deposit vault at a bank, and Ironside begins to unravel the details of the crime. There is only one apparent suspect, and the Chief is certain that he is not guilty; but as he investigates further, his own life may well be in danger.

A friend of Mark's is being unfairly shaken down by a crooked loan shark with crippling interest demands. Worried for his friend Mark goes undercover, despite objections from the Chief, and sets himself up as a potential customer in the hope of digging the head of the operation out of the woodwork.