The platoon finally gets to grips with the enemy when it has to guard some Nazi submariners. But the Germans turn the tables on Mainwaring and try to escape, resulting in Jones ending up with a grenade down his trousers.
The platoon decides to give a party to the visiting American troops. When the Yanks start to get fresh with the platoon's girlfriends, all hell lets loose.
When classified news is shared that the King is to travel through Warmington-on-Sea by train, Capt. Mainwaring and the platoon are detailed to form a guard of honour. Then, when another train breaks down on the main line, blocking the King's route, the platoon swings into action.
The platoon has gone to a camp to undergo an efficiency test. Meanwhile Walker has a van load of onions he's sold to Hodges, who isn't letting them out of his sight, thus he has pursued the platoon to the camp. Later, with no blank shells to use on the test, Mainwaring has a brainwave regarding what to use as ammunition!
When a relative of Sgt. Wilson dies, he inherits his title. Then, when a Russian factory worker visits the town to boost Anglo-Russian relations, Mainwaring is asked to present the key to the town - until the mayor hears about Wilson's title, and asks Mainwaring to step down.
The platoon gets lost on a wild and stormy night and has to take shelter in an old and deserted house that is used for training tracking dogs. When Pike gets his uniform wet he changes it for an old German uniform, but when the dogs get loose, they chase Pike and the platoon across the fields.
Note: Last regular appearance of James Beck as Pte. Joe Walker. Walker only appears in the external scenes as Beck was taken ill shortly before the studio scenes were recorded.
Capt. Mainwaring has gone into hospital for an operation on ingrowing toenails. Meanwhile Wilson as acting CO has asked the vicar and the verger to join the platoon to make up the numbers.
Note: This is the first episode not to feature James Beck as Pte. Joe Walker, although Beck is still included in the closing credits.