A woman, director of advertising films, catches the eye of a mysterious young woman dressed in white during an evening of dancing on the terrace of a bar and is fascinated by her.

A vicious serial sex killer is on the loose, and landscape gardener and shop-window outfitter Loris is the prime suspect, thanks to his unfortunate habit of getting caught in compromising situations (for which there is always a totally innocent explanation that the police fail to spot). Undercover policewoman Jessica is assigned by eccentric police psychologist Taccone to follow Loris.

Edward Sacchi is a wealthy and apparently content married man but underneath he is driven by a desire to seduce and discard women. One of his conquests, Lucy, falls in love with him and when spurned, commits suicide. Edward is shocked but continues as before. Each of his lovers are subsequently murdered and he is arrested. However, his wife saves him by arranging an appointment with the real killer...