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.

Godfrey asks to leave the platoon because he doesn't want to fight. Mainwaring is furious and the rest of the platoon shuns him until they find out that he was a hero from The Great War. So he rejoins the platoon as a medical orderly.

The platoon is assigned guard duty on an isolated, disused pier for a week. However, thanks to Pike's poor judgement over how to moor the boat, they end up stranded with no contact with the mainland and no food. Attempts at Morse code only prompt Hodges to pursue the platoon to get them to 'Put that light out!' and he ends up stranded himself. If that wasn't enough, Jones spots a stray mine under the pier, but does Hodges have a solution that'll 'bowl them over'?

Capt. Mainwaring decides to enlist women to the platoon to assist with the war effort. After initial interviews go rather less than satisfactory, a Mrs. Fiona Grey walks into his office and into his life. Mainwaring is flattered that Fiona not only has similar views to him about the war, but also is complementary about his persona. He finds himself falling in love. Unfortunately the men very quickly realise and start to gossip behind his back and Fiona decides to leave, but can Mainwaring get to the station in time to stop her?

The bank takes a direct hit during an air-raid, but the bomb fails to explode, leaving Mainwaring and Wilson stuck in the vault with it. When the bomb disposal officer leaves to collect the right tools, the platoon members take matters into their own hands.

The platoon captures a runaway barrage balloon and while trying to secure it, Capt. Mainwaring is carried aloft.

Capt. Mainwaring has the idea of small armed patrols to wreak havoc upon the enemy using a small re-processed boat the bank has acquired. After a practice on the river they get lost in the fog, and thinking they have drifted across the channel and are about to be captured by the Germans, they are in for a shock when they find out where they really are.

While the platoon is at a training camp, Mainwaring gets drunk with the other officers during the night and misses the live grenade training the following morning. Later during the training one of the grenades lands in Jones's van and Mainwaring rides to the rescue.

When the church bells start to ring, the platoon leaps into action. Jones takes half the platoon to Godfrey's cottage to set up a machine gun post while Wilson, not knowing where Jones has gone, also heads for the cottage where they both mistake each other for the enemy and prepare to attack.

During home guard manoeuvres LCpl Jones, disguised as a log and helped by Frazer in a diving suit, floats down the river in order to attack the Eastgate platoon's headquarters.

The platoon is manning the local lighthouse and accidentally switches on the light and can't find a way to switch it off. During an air raid they must find a way to cover up the glare.

LCpl. Jones goes to a reunion of his old regiment. While he is away an old comrade who fought in the same battle joins the platoon and accuses Jones of cowardice. Upon his return Jones has to tell the real story.

Capt. Mainwaring promotes Frazer to Lance Corporal, thus causing friction between him and Jones. When Frazer starts getting above himself, Mainwaring cancels the promotion.

When a low-flying German aircraft attacks Warmington-on-Sea, the platoon, under the command of LCpl Jones, fires at the aircraft and uses up all its ammunition. Mainwaring is furious and orders an investigation.

Capt. Mainwaring is found not to have held the King's Commission so he is reduced to the ranks and Sgt. Wilson takes over command of the platoon. After a disastrous war game against the Eastgate Platoon, his men ask the Colonel for him to be reinstated.

The search begins for a spring clip for a Lewis gun that Frazer has lost whilst cleaning it. The trail leads them through Frazer's workshop to a Funeral Director, to Mr. Bluett's dining room table, to a graveyard. The platoon stops at nothing, committing various crimes including house breaking and grave robbing to get the clip back. But will they find it in time to save Frazer from a court martial?

Mainwaring watches a film reel at the cinema which shows Winston Churchill inspecting Army troops and their mascot - a ram, of course where Mainwaring's concerned. If another platoon has a mascot, so must his. Sponge volunteers one from his farm but they have to catch it first; something that of course ends in complete disaster with Pike up to his neck in it - literally. Meanwhile the town parade is being organised and of course Mainwaring wants the platoon to lead, but Hodges has other ideas...

In a cricket match between the platoon and the ARP wardens, Chief Warden Hodges has a secret weapon up his sleeve: he plans to recruit Ernie Egan (played by England's fast bowler Fred Trueman), a professional cricketer. But all does not go as planned.

Sgt. Wilson becomes a manager of his own branch and gets a commission on the same day. But hours later his new branch is destroyed during an air raid. Mainwaring offers him his old job back and his former rank.

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 the ARP Headquarters has been destroyed, Hodges and the wardens move into Mainwaring's office and the two of them start arguing over space. Later the chimney catches fire and they have to work together to put the fire out.

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.

Walker is finally called up but Mainwaring tries to get his call-up deferred because of his value to the platoon, but he is still conscripted, only to find out that he is allergic to the army's corned beef.

Capt. Mainwaring is giving a lecture on recognising enemy agents when he learns that for every Nazi captured there is a reward. Later on Jones and Walker capture two Luftwaffe airmen, although a Polish officer intends to claim the reward. Back at HQ the airmen escape on Godfrey's watch.

Just when the platoon finally gets its 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.