One man's good luck leaves a very bad impression in this comedy. Johnny Dalton (Frank Sinatra) and Mildred Goodhug (Jane Russell) are two tellers working at the same bank who have fallen in love and want to get married. However, neither is making much money, and Johnny doesn't want to set a date until he has some savings in the bank. Emil J. Keck (Groucho Marx), a pal of Johnny's who waits tables at a diner, suggests that it can't be that difficult to "find" some money in a bank, but Johnny prefers to stay on the straight and narrow. However, Johnny enjoys a sudden windfall after he happens upon "Hot Horse" Harris (Nestor Paiva), a racetrack tout being beaten up by ne'er-do-wells, and breaks up the fight. Grateful Harris places a bet on a "can't lose" horse in Johnny's name, and suddenly Johnny is $60,000 richer. But before Johnny and Mildred can enjoy their good fortune, word leaks out that someone has embezzled $70,000 from the bank, and the suddenly prosperous Johnny seems a likely suspect. Double Dynamite was produced under Howard Hughes' supervision at RKO, but bad blood between Hughes and Sinatra led to "Ol' Blue Eyes" receiving third billing for the film's leading role; the film also spent over a year on the shelf before finally hitting theaters.
by Mark Deming synopsis