When a pretty Wren faints in a crowded train, Private Bud Flanagan and Captain Ches Allen are quick to render first aid. But over Bud's head, a heavy kitbag wobbles; it falls and scores a direct hit, knocking him unconscious. What follows is a dream sequence involving Ches, the Wren and Bud himself in a series of hilarious adventures as well as a magical medley of the duo's best-loved musical numbers!

A night watchman is being bludgeoned, as a safe is cracked open in the offices of the District Food Controller. A list of wartime foods to be rationed is stolen, and the police fear gangsters are planning to sell the foods on the black market. As the office charwoman, Old Mother Riley's fingerprints are all over the safe, and she becomes the police's number one suspect. To prove her innocence, Mother Riley turns detective, adopting various methods and disguises to track down the villains.

George and Katherine plan to marry but war breaks out. When he returns on two weeks leave, but has his marriage proposal put down by Katherine, George enters a relationship with another woman.