Barney Lincoln, a wealthy American playboy, has one exciting date in London with an attractive dress designer named Angel McGinnis and then leaves for Geneva. Once there he breaks into the Kaleidoscope card factory and etches secret marks on the printing plates used in making playing cards for all the European gambling casinos. He then goes to Monte Carlo, is reunited with Angel, and makes a fortune because of the marks on the backs of the cards. After a tour of other European casinos, where he continues to win more money, Barney returns to London with Angel. To his dismay he learns that while they were in Monte Carlo, Angel became suspicious and alerted her father Manny, a Scotland Yard detective, who now knows all about Barney's deception. Manny then reveals that in return for his freedom Barney must assist in capturing Harry Dominion, a narcotics smuggler with a weakness for poker. Accompanied by Angel, Barney sits in on a game with Dominion and wins every hand--even one played with an unmarked deck. Not accustomed to losing, Dominion uses Angel as bait to lure Barney to his country estate, where he gets back his money by force. Barney and Angel attempt to escape and are almost run down by Dominion's henchmen. But Manny and his men from Scotland Yard arrive in time to break up the dope ring and rescue Barney and Angel.
