Harry Fabian (Widmark) is an ambitious American hustler and Confidence trick operating in London, always looking for a better deal. He maintains a fractured relationship with the honest Mary Bristol (Tierney), nightclub owner and businessman Phil Nosseross (Sullivan), and Helen (Withers), who is Phil's estranged wife. While attempting a con at a wrestling match, Fabian witnesses Gregorius (Zbyszko), a veteran Greek wrestler, arguing with his son Kristo (Lom), who has organised the fight, and who effectively controls all wrestling in London. After denouncing Kristo's event as tasteless exhibitionism that shames the sport's Greco-Roman traditions, Gregorius leaves with Nikolas (Richmond), a fellow wrestler. Fabian catches up with the two and befriends them, having realised that he can host wrestling in London without interference from Kristo if he can persuade his father to support the enterprise.