Patricia Foster, an industrial designer, causes chaos when she sells a secret cosmetics formula to a rival company.

The lazy, goldbricking Snafu is asleep, when he is suddenly awakened by the morning bugle call. He doesn't want to get up, so the "Goldbrick fairy" appears. The fairy sings to him several things to do to avoid completing any of his duties. After many successful sleazy attempts to avoid work, the fairy pulls off his disguise and reveals he is actually an enemy Japanese, who fooled him and sabotaged his army's entire defense.

About the only thing kept in this film from Preston Sturges origianl story for "The Miracle of Morgan's Creek" is a girl that gets drunk, gets married, gets pregnant and doesn't even remember any of it. A major dirrerence is that "The Miracle of Morgan's Creek" was a classic comedy and "Rock-a-Bye Baby" isn't. This time out, Clayton Poole (Jerry Lewis) is a small town TV repairman who is still in love with his former hometown sweetheart, Carla Naples (Marilyn Maxwell), who is now a famous movie queen. When Carla becomes pregnant due to a hasty marriage in Mexico, which she has forgotten about, the studio tells her a baby will ruin her career so she turns to Clayton, the only person she can trust, and he agrees to care for the baby when it is born. Carla gives birth to triplets and Clayton finds he must get married before he can adopt them. He marries Sandy (Connie Stevens), Carla's younger sister who has always loved him. The press learns about Carla's triplets and she tells reporters she is secretly married to Clayton. Clayton, having rapidly gone from no wife and kids to two wives and three kids, goes into hiding. He returns after several months---nine to be exact for those old biddies who are counting---and learns that Sandy has given birth to quintuplets.