As all the road signs have been removed from the area, the platoon is ordered to put up temporary ones to help a large convoy on manoeuvres that is due to drive through the area, but due to the condition of the ground Jones's van gets stuck in the mud.
Pike gets his head caught in the park railings and the platoon is summoned to help. Meanwhile a large bomb has exploded near the town and has put out the gas and water supplies. When Mainwaring returns to hear what has happened he puts the town under martial law.
On a field exercise acting as commandos meeting a secret agent, represented by Mainwaring, the platoon must trust no-one for GHQ has sent out counter agents to catch them. The appearance of a gorilla compounds their problem.
The platoon dresses up as Morris Dancers as part of a carnival to raise money for the town's Spitfire fund, which is still £2,000 short. A Lady Godiva figure will lead the parade but there is confusion over who this will be.
Lady Maltby offers her Rolls Royce to Capt. Mainwaring for use as his staff car. After the car has been disguised with camouflage paint, it has to be repainted black, because the mayor's car has run out of petrol, and there's no official car to greet a visiting VIP.
After the platoon accidentally shoots a turkey, attempts are made to return it to the local farmer, but he will not accept it so the men come up with the idea of providing a dinner for the local OAPs.