René is sitting outside his café, polishing the cutlery. This is so he can observe Edith as she goes into the butcher's shop. As she does, he has ten minutes to cuddle with his waitresses Yvette and Maria. As he cuddles with Maria in the backroom, they are interrupted by Michelle, who tells him that the airmen need help digging the tunnel into the prisoner of war camp. The undertakers cannot help, since they are digging graves to put all the loose earth in.
In Fanny's bedroom, René and Edith put new batteries in the radio. Fanny complains that the Germans have taken her painting of the flowers. René and Edith think it was only a "worthless painting", but Fanny says it is very dear to her. It was given to her by a "penniless artist who went round the twist". He said if she would not marry him, he would cut off parts of his body and send them to her and he did send his ear. As they ask her what his name was and she replies "I called him Bobby. I thought Vincent sounded too poofy" they realise that the painting was made by the famous artist Vincent Van Gogh. The next moment, London calls on the radio and asks "Has old mother Hubbard got together with Miss Muffet and Little Boy Blue?" (meaning "Are the airmen inside the prisoner of war camp?"). They reply, in code, that they are not in yet.
Herr Flick and Von Smallhausen are sitting in Herr Flick's office, listening in on the radio transmission. As Von Smallhausen was educated at Oxford, he recognises the words as nursery rhymes. He remembers that Old Mother Hubbard had a cupboard ("airmen can hide in a cupboard"), Little Miss Muffet had a tuffet (made by moles living underground) and Little Boy Blue had a horn (which Herr Flick associates with "French horn"). This makes them figure out that the airmen have been hidden in a cupboard by the French underground movement (the resistance). As Von Smallhausen also remembers that Old Mother Hubbard was looking in the cupboard to find a bone for her doggie, Herr Flick notes that bones can be found at a graveyard, where there has been much digging lately. They therefore decide to investigate the graveyard.
Captain Hans Geering is sitting alone at the café. He is downhearted because the colonel will not speak to him. The reason is the shooting the night before, where Hans's gun was used. René tries to cheer him up and, holding his hand and looking affectionately at him, the captain assures him he is very grateful and cannot thank him enough. At this very moment, Lieutenant Hubert Gruber comes in and is not entirely comfortable with the intimacy the captain shows to René. The next second, Colonel Kurt Von Strohm enters, greeting René and Hubert, but ignoring Hans. He asks Hubert about the status of the painting and he informs him, that it is safe in his quarters. The colonel asks him to make two copies of "The Fallen Madonna with the Big Boobies" - one to give to Hitler and one to give to Herr Flick. As Hubert informs him that General Von Klinkerhoffen wants a copy of the Van Gogh painting (to give to Hitler) they decide to make Hubert make another copy, to give to the general, so they can sell the original after the war.
Outside the church, there is much grave-digging going on, in the rain. Inside, Herr Flick is disguised as a priest and Helga as a nun. As they are to wait and observe, Helga asks if he wishes her to kiss him. He tells her not to while she is dressed as a nun - it would give offence. She asks whom it would offend and the reply comes from Von Smallhausen, who shows up dressed as a bishop, that it would offend him. That very moment, a French girl shows up in front of Herr Flick and gives a confession to him, about having done very dark and naughty deeds. He gives her the penance of going home and saying 100 "Heil Hitlers".
The airmen are digging away in the tunnel. Michelle asks them how they are doing and tell them they will get help from the café. Meanwhile, some British prisoners of war are digging from the other way.
Monsieur LeClerc enters the café, disguised as a policeman. He tells René and Edith that they are to go at once to the mortuary to help with the digging. Edith then tells him to bring her mother down, so she can look after the bar. Then, officer Crabtree shows up, informing them that he has hushed up the shooting of the two tarts, that the graveyard is under surveillance from the Gestapo in disguise and that the airmen are digging away. He is to escort the café gang to the mortuary and as a cover; Edith tells the German officers that they will go to the mortuary to pay their respects to the two tarts that were shot in the café the night before. When they have left, the colonel starts talking to the captain again and says they should follow the café gang. However, the captain reminds him that the general told them to watch the café and as that is much more comfortable; they decide to "follow orders" instead. However, when Fanny comes down and starts singing La vie en rose, they decide to follow the gang instead. After a while, the café is empty of customers, because nobody wants to hear her bad singing.
After Herr Flick has given a sermon, he is still suspicious of the grave-digging and decide they should go to the mortuary to investigate.
The airmen are having a break, but when somebody is coming, they have to lie down and play dead. Fortunately, it is Michelle and the café gang. As they have heard scratching sounds down the tunnel, they are apparently close to breaking through to the prisoners of war digging out. Suddenly, monsieur Alfonse comes out of the tunnel, with a pot full of earth. The airmen get down the tunnel again, continuing digging, while the others are to form a chain with pots to heave the loose earth out of the tunnel. As they are doing this, the colonel and the captain show up at the mortuary. At the same time, the airmen and the prisoners of war break through in the tunnel. However, as the Germans are approaching, they (and Michelle and the café gang) are all forced to go up the tunnel into the prisoner of war camp.
Monsieur Alfonse greets the two Germans who are rather suspicious, as they have seen René enter the mortuary, but not come out. They find a coffin full of earth and earth on the floor in front of a marble tomb. They open it and, discovering the tunnel, go down it.
In the camp, the other prisoners are rather surprised at seeing Fairfax and Carstairs - and Michelle and the café gang. As there is an inspection in five minutes, they must be hidden. Meanwhile, the colonel is stuck in the tunnel and as the captain pulls him a bit forward, the tunnel caves in behind them. Therefore, they must crawl ahead, until they have also come out in the camp. An announcement is heard about General Von Klinkerhoffen coming to inspect the prisoners in five minutes. However, they manage to disguise everybody, including the German officers, and line up outside the hut. The general inspects them, but does not find out who they really are. As he leaves the camp, all the prisoners whistle the Colonel Bogey March.