World War II is raging, but in the French village of Nouvion, café owner Rene Artois wants only a quiet life, plus some slap and tickle with his waitress Yvette behind his sour wife Edith's back. To this end, he keeps in with two German officers who are regular café patrons, Kurt Von Strohm and Hans Geering. He is therefore alarmed when Michelle of the Resistance declares his house a safe house for two British airmen who have been shot down and who don't speak a word of French. He is also to host Roger Leclerc, a forger and old flame of his mother-in-law Fanny, who was sprung from jail by the Resistance but, due to a misunderstanding, mistakes Hubert Gruber, a German officer who turns out to be gay and fancies René, for the forger. Geering and Von Strohm discover the hidden British airmen, but when Herr Otto Flick of the Gestapo arrives, they agree to help. This is because Flick is after a favourite painting of Hitler's, "The Fallen Madonna with the Big Boobies," which they wish to keep for themselves. To this end, they give their uniforms to the escaping airmen.

Colonel Von Strohm wants to hand René over to the Gestapo along with the painting of the fallen Madonna with the big boobies by Van Klomp to get rid of Herr Flick, but René convinces them that it would be a better idea to try to forge the painting, give that to the Gestapo and split the money from the painting after the war. Captain Hans finds out that putting cheese in one's ears improves the sound of madame Edith's singing.

The airmen, wearing German uniforms, are captured by the Maquis but escape and burn the uniforms, taking clothes off scarecrows instead before disguising themselves as onion sellers. Von Strohm and Geering, now without uniforms, are angry with Rene and he is given two carrier pigeons to send to London for replacement uniforms. He uses the radio transmitter hidden under Madame Fanny's bed instead when Edith kills and cooks the pigeons.

Michelle brings a bottle of nitroglycerin to the café for safe keeping until it is time for her to use it to blow up a German train. However, as it is in a gin bottle, Edith thinks it really is gin and gives some to Madame Fanny. René and the two German officers meet the plane bringing their uniforms but on board there is only a Jewish tailor who takes their measurements. He does, however, take the painting of "The Fallen Madonna with the Big Boobies" back to London to be copied.

General Von Klinkenhoff of the German High Command is to arrive in Nouvion by train. Von Strohm and Geering are not keen to see him as he will find out about their incompetence and allow themselves to assist the Reistance in blowing up his train. The General survives and various suspects are arrested but ultimately only Rene is identified as a saboteur and is sentenced to be shot. Various people try to help him escape from prison but in vain. However as Gruber prepares to supervise the execution Von Strohm substitutes harmless wooden bullets for the lethal real ones.

Rene's funeral is to be arranged by the village undertaker Monsieur Alphonse. Flick, along with his girlfriend, Private Helga, will be watching on the off-chance that the mourners will include other Resistance members who can then be arrested,but the plan is leaked so that Monsieur LeClerc will pose as the priest and no Resistance members will attend. Rene himself is passed off as his twin brother, also called Rene, come to pay his respects. In the absence of a body, Michelle hides some anti-tank missiles that she has been given in the coffin but of course it falls off the hearse, causing an explosion.

The Resistance capture Von Strohm and Geering, whom they intend to shoot in return for the death of the late cafe owner. The task of shooting them is to be given to Rene in revenge for his brother's slaying. Fortunately he is able to enable all three of them to escape in time to meet the plane bringing the forged painting back from England, which they intend to return to Flick. Unfortunately, it is only after the hand-over has been accomplished that they discover that they gave him the genuine original and they have the copy.

Hearing that Flick intends to send the painting back to Berlin the next day, Von Strohm directs Rene to make the switch that night. A diversion is arranged in the form of a Hitler Youth Dance, in which local girls dressed in Bavarian costumes will perform for the Gestapo officer's delight. Meanwhile, Rene and Edith, wearing the German uniforms that arrived on the plane, will take the forgery back to Flick's office. Unfortunately the guard takes the painting from them and sends them away. Now Flick has the original, the London forgery and one he made himself to work a fiddle that would get him money to marry Helga after the war. Meanwhile, the airmen are smuggled to the coast but, on hearing that there is no submarine for them and they must row home, return to the village.