A former secret agent, who retired and wrote a first novel which tells the eventful adventures of his hero "Le Léopard ", comes back to work, reluctantly helped by an old maid.

The murder of a bandit gives a policeman the opportunity to unmask the activities of a spy.

A woman's father, a scientist, receives repeated death threats and eventually ends up dead. Receiving no help from the police, the woman begins to realize that she is next.