After listening to a radio broadcast asking for men to form what was to become known as the home guard, George Mainwaring, a local bank manager, decides to act and form the platoon on his own. He appoints himself as Captain and recuruits his chief bank clerk Arthur Wilson as the platoon sergeant as well as enlisting the banks office boy Frank Pike. Several of the local tradesmen, including James Frazer; a philatelist shopkeeper, retired shop worker Charles Godfrey, Jack Jones the butcher and black market business man; Joe Walker also volunteer their service for 'King and Country'.. And so, The Walmington-On-Sea Home Guard was born.

With the shortage of weapons, Capt Mainwaring goes to the local museum, to see if any of the guns that are on display can be used, by the platoon.

Capt Mainwaring worried about the lack of weapons gets a visit from a Capt Square an old soldier who offers to donate some guns from his collection providing that he can take command of the platoon. Mainwaring agrees until he sees the state of the guns.

Capt Mainwaring is giving a lecture on recognizing enemy agents when he learns that for every Nazi that they capture there is a reward Later on the section on patrol capture two German flyers but back at HQ Godfrey accidently let them escape

Just when the platoon finally get their uniforms LCpl Jones is told that unless he can complete the assault course in 15 minutes he will have to leave So Mainwaring and the rest of the platoon think of a plan to help him

When news that the Prime Minister is to pay a visit to the area a shooting contest is held to see which of the local platoons will form the honor guard Walker gets a crack shot from the theatre touring show ( Barbara Windsor ) to take part as a member of the platoon but a surprise is in store for everybody