When Mrs Tremaine is mysteriously gassed to death, ambulance driver Frank Jessup meets her elegant but sexy stepdaughter Diana, who quickly catches up and falls in love with him. Seduced by Diana, Frank soon becomes Tremaine's chauffeur, but he begins to suspect the danger beneath her ostensibly sweet words. When he showed signs of escaping, Diana planned to get him so deep that he would never get out.
In California, ambulance driver Frank Jessup and his partner traveled to a Beverly Hills mansion to help gassed millionaire Lady Catherine Tremaine, but her doctor had prescribed her medicine. On his way out, Frank encounters Catherine's stepdaughter, Diane Tremaine, who follows him in a Jaguar. A few hours later, they went to a restaurant, Frank made an excuse to keep his girlfriend Mary Wilton away from seeing her, he went on a date with Diana, and they went to a nightclub. Diana fell in love with Frank, and the next morning, she met Mary and told her what Frank had done with her. Frank and Mary are efficient mechanics, so they're saving up to open a garage. Diana persuades Frank to work as a driver for her family for a higher salary. Soon Frank learns that Diana hates her stepmother, and he decides to quit. But Diane seduces him, and he lives with the Tremaine family. When the Tremaines are involved in a fatal car accident, Diana and Frank are prime suspects for police, who are charged with murder. Their only chance now is the tactics of highly effective defense attorney Fred Barrett.
