Blue-collar Joe Lampton (Laurence Harvey) secures a job in a small town ruled by a rich industrialist, vowing to climb to the top by courting the head honcho's daughter. But when Joe's plans get scuttled, he turns to Alice (Simone Signoret) -- an older, married woman -- for comfort. Setting aside his feelings for Alice, Joe seduces, impregnates and weds the boss's daughter, only to realize that his "coup" has cost him his soul.