A female private detective, Harriet Zapper, is hired by a rich old man to find his missing children, and becomes involved in counterfeiting and murder.

A group of crooks accidentally kill an elderly shop assistant while stealing the keys to the jewellery shop where she works. When his superiors think that the case is better handed over to Scotland Yard, the local detective inspector, Sparrow, decides to go solo to investigate the crime himself.

The cat and mouse game between government agents and a spy ring that has taken secret documents from a plane crash in Germany, not far from an US military research centre.

A renowned safecracker and his crew try to rob a bank by entering the vault through the sewer system.