A man with a sandwich-board (advert) wanders around London meeting many strange characters.

Simon Templar is hired by a friend in the book publishing trade to protect one of his stars, a secretive recluse named Amos Klein who writes a popular (and lucrative) series of adventure novels about a manly and suave spy.

The Cat Gang is a group of precocious British kids. They have a habit of hanging around a grown-up customs official who wishes that they'd beat it. But the Gang comes in handy when a smuggling gang arrives on the scene.

Three criminals plan to break out of prison the day before their release in order to carry out a daring jewel robbery, intending to establish the perfect alibi by returning to jail afterwards. First however they must get out, a task made more difficult by a new, stricter prison officer.

Young nurse Jill Holden gets involved with an extortion gang targeting Mrs Cheam, one of her patients. When Mrs. Cheam is murdered, Jill becomes a suspect and must clear her name.