When World War Two breaks out, the small seaside town of Walmington-on-Sea finds itself less than ably defended by the elderly and inept members of Captain Mainwaring's home guard unit. Put on manoeuvres by a visiting Major-General, Mainwaring's men manage to bungle one task after another. However, when a group of Germans from a scout plane take the Mayor hostage at the church hall, the clueless soldiers might still have a chance of saving the day!