A veteran homicide detective who has witnessed his socialite girlfriend kill her husband sees his inexperienced brother assigned to the case.

Steve Morgan kills a man in a holdup and hitches a ride to Los Angeles with Fergie. At a gas station, they pick up two women. Encountering a roadblock, Morgan takes over and persuades the party to spend the night at an unoccupied beach house. The police close in as one by one, the others learn that Morgan is a killer.