During a cruise from Trieste to Dubrovnik, professional cardsharp Rooney and his accomplice Goldy fleece a pair of professional gamblers, Broadfoot and Cozzier. The four gamblers then agree to join forces to swindle a wealthy victim in Dubrovnik, using Candace, a beautiful fellow passenger, as bait. A phony water skiing accident in Dubrovnik enables Rooney to meet their victim, the Italian aristocrat Del Isolla. Rooney and Candace begin a romantic relationship, but Rooney refuses to become too involved for fear of being distracted from the pending swindle. The entire party is invited to the Del Isolla villa where a fight is arranged between Koboyashi, Rooney's Japanese valet, and Nono, the Del Isolla houseboy, in order to warm up Del Isolla's gaming spirits; this is followed by an all-night poker game in which Del Isolla loses heavily. Del Isolla offers Rooney his IOU which Rooney intends to convert to cash in Geneva before joining his new accomplices for another swindle in Warsaw. As security, Rooney gives Broadfoot and Cozzier $50,000 in cash. At the airport, however, Rooney meets Del Isolla and his wife and learns that they are really actors hired by Broadfoot and Cozzier in an elaborate plot to cheat him. Undaunted, Rooney finds Candace at the airport, tells her what has happened, and convinces her to stay with him. The two return to Dubrovnik empty-handed but happy.