 Unmarried police detective Carella sees Jocelyne, a sexy old flame who is being trailed by an Englishman.Any thoughts of taking up with her again are put aside because he has to investigate the assassination by a single shot from a long-range 0.22 rifle of Forest, a prominent local businessman.The widow is no help but the man's stepdaughter Sandra mentions an associate Barroyer, who later that day is killed in exactly the same way.