Retired safe-cracker Sam Morrissey is approached by Jack Harrison, an advertising man representing the Holdwell Safe Company, with a proposition. Jack wants Sam to try to break into a Holdwell safe on television - and, of course, he firmly believes it can't be done. However, inside the safe there will be twenty-five thousand dollars, and the money is Sam's to keep if he can crack the safe within three hours. Sam accepts the challenge - but he is not a man who likes to leave things to chance.