The Colonel orders Mainwaring and the platoon to make a training film with a couple of well-known actors, but unknown to Mainwaring they are to play the Germans. Mainwaring refuses to take part but the rest of the platoon is still ordered to do so. When the filming is cancelled, Mainwaring and the men, still dressed as German soldiers, are spotted in the local pub and the alarm is raised.

Pike finally gets his call up papers and is to join the RAF, but when his blood donation to the Red Cross is checked it is found to be from a rare group and he is designated exempt from military service. Then he has to find a way to break the news to the platoon.

At the bank the door to Mainwaring's office is replaced with a paper door. Adding insult to injury of not having a proper door, Mainwaring is even more annoyed at the fact that Pike, the Colonel and Jones manage to destroy it within minutes of it being installed. Godfrey's cottage is due to be demolished to make way for a new airfield but no-one can bring themselves to break the news to him until Jones finds out that he already knows. In the end Frazer, knowing the family history of the General in charge, blackmails him to get the airfield moved 200 yards.

Capt. Mainwaring gives a lecture on field craft in the vicar's garden, covering what to eat and how to erect a tent. Later, apart from having to put up with the vicar, verger, Hodges and a gang of boy scouts, their field manoeuvres are also interrupted by three German airmen who have been shot down and are trapped in their dinghy in the middle of the lake. "Hӓnde hoch! Hӓnde hoch!"

LCpl. Jones has problems with his bank account. When Mainwaring tries to help, he finds that the trail leads through the platoon, on to Mrs. Pike, and ends with Mr. Hodges.