The war effort is wearing down the people of Walmington-on-Sea. While practising on a firing range, Mainwaring is told to keep the noise down and Hodges is verbally assaulted for his efforts as chief warden. Mainwaring decides to scare his townfolk by getting the platoon to dress up as fifth columnists and marching through the countryside 'asking ze questions!'

Mainwaring is to umpire in a war game exercise so he gets the use of a car. Pike meets a girl and uses the car to take her out, but they stay out all night, leaving the whole town scandalised.

During a Wings for Victory fundraiser, the platoon reenact the battle between St George and the Dragon, but friction starts when Hodges and the wardens plan the same thing.

Frazer, whom the town has been under the impression has meagre earnings, is, as a matter of fact, rather wealthy. Doctor McCeavedy alerts Mainwaring, who alerts Jones and very soon Frazer's fortune is the subject of town gossip.

The platoon takes over from the regular army in guarding some vital telephone wires. During an air raid, a bomb lands in the wires and a way has to be found to get it down before it explodes.

Jones wants to wed Mrs Fox but must get Mainwaring's permission. During the reception, an invasion alert is called and Jones spends his wedding night on the beach on guard duty.