Academy Award winner Warren Beatty stars as a handsome playboy cardsharp who discovers a foolproof method to beat the casinos in Kaleidoscope. Barney Lincoln (Beatty) breaks into the factory the manufactures playing cards for the large European casinos and etches a small mark that only he can read on the backs of all its cards. Everything goes smoothly until his girlfriend's policeman father discovers the reason for Lincoln's incredible winning streak ... and forces Lincoln to work undercover for Scotland Yard.