While on a mission, American astronaut Captain Tony Nelson is forced to make an emergency landing that will forever change his life. On a deserted South Pacific island, Captain Nelson happens upon a bottle containing a beautiful two-thousand-year-old female genie named Jeannie. Rescuing her from the bottle nets Tony the requisite three wishes, and then some, when Jeannie pledges total devotion to her new "master".

Lieutenant Rip Crandall is hoodwinked into taking command of the "Wackiest Ship in the Navy" – a real garbage scow with a crew of misfits who don't know a jib from a jigger. What none of them knows, including Crandall, is that this ship has a very important top-secret mission to complete in waters patrolled by the Japanese fleet. Their mission will save hundreds of allied lives – if only they can get there in one piece.

This musical reworking of Too Many Husbands (1940), features Grable as a top singer and dancer who's been widowed by WW II. She marries her late husband's songwriting partner, Gower Champion, but the new marriage is thrown for a loop when Lemmon, her first husband, turns up very much alive and eager to see Grable.