While the RAF are bombing the town, René sneaks back through the town square to find cover. As he tries to signal to the bombers to stop dropping the bombs (by flashing his torch), officer Crabtree shows up and forbids him to do so.
General Von Klinkerhoffen and colonel Von Strohm are both hiding from the bombings; the general under his bed and the colonel under the table in his office. The general telephones the colonel and since neither of them wants to appear a coward, the colonel says he is standing on his balcony, directing the anti-aircraft fire, while the general says he is on the roof of the chateau with a machine gun. Unfortunately, captain Bertorelli comes into the colonel's room and asks him what he is doing under the table, which the general overhears on the phone.
During the air raid, the airmen watch it from a small attic window, cheering their fellow airmen as they continue bombing. Meanwhile, herr Flick tries to interrogate Helga, in the presence of Von Smallhausen. He complains that she does not answer his questions, but she says it is because she does not know the answers. Herr Flick then turns on a fan with light behind it. It revolves at the exact speed of the alpha rhythms of the brain, hypnotising anybody who looks at it and rendering the person unable to say anything but the truth. As he turns it on and asks "What is your real name?", Von Smallhausen answers truthfully "Bobby Cedric Von Smallhausen". He is sent away, but Helga informs herr Flick that the device has no effect on her. She is then released, on condition she continue to gather evidence of the plot by the general, the colonel and the lieutenant to blow up Hitler.
The next day, Edith delivers the film from the spy camera to monsieur Alfonse for him to develop it. When they are alone in his dark room, he once more tries to court her, but she says she has promised to marry René. Monsieur Alfonse then tells her of René's affair with Yvette. This makes her very cross and she says that, after confronting René, if he cannot give a satisfactory explanation, she will leave him for monsieur Alfonse.
Colonel Von Strohm and lieutenant Gruber are sitting at an outdoor table in the café, when Helga arrives informing them of herr Flick's suspecting them of plotting to blow up Hitler. They deny it, but are not sure about the general; thus, they also want Helga to report the general's moves. While sitting there, monsieur Alfonse shows up with Edith riding in his hearse. When they have arrived at the café, Edith wants monsieur Alfonse to come inside, so they can confront René with the news. He does not want to (being afraid of René), but says he will not go inside because there is nobody to tend to his horse and that René is much bigger than he is. The next moment, Fanny looks out her window and, thinking the undertaker has come for her, starts throwing flower pots at him, driving him away.
Edith goes straight into the café, confronting René about his alleged infidelity. He denies by simply and calmly answering "No" to her questions - and she believes him. She then gives him the developed photograph of the safe and they summon monsieur LeClerc, who is tuning the piano to match Edith's voice, to have a look at it. They ask if he can open such a safe and he says he can – with a key. He could also manage it with some plastic explosive, fuse, and a detonator. They decide to hand over the list of these things to Michelle, so she can provide them.
The three Germans are still sitting at the café table, when the general shows up in the town square in his car. Privately, he orders the colonel to invite Helga (whom the general finds very attractive), to dinner at the chateau that same evening. During the meal, the colonel will simulate a stomachache and leave the general and Helga alone. He is also to provide music for the evening - with real live musicians.
Later in the evening, the colonel, the lieutenant and the captain are sitting at the café, listening to Edith's singing. When she is done and they have received more wine, monsieur LeClerc enters, disguised as a window carpenter. He cries out he has some "pathé" to sell (which is really plastic explosive) and captain Bertorelli nearly buys it (since he needs some to mend his windows), before René takes care of it and Yvette calls them all (René, Edith and monsieur LeClerc) into the backroom, where Michelle wants to speak to them.
She informs them of her plan to get to the safe in lieutenant Gruber's room. A smoke canister will be dropped down his chimney and as he evacuates the room, René and monsieur LeClerc will smash the window and enter the room, disguised as firemen with gasmasks. For this purpose, Michelle has acquired a fire engine and a ladder. After officer Crabtree has come into the room, through the window, with the fuse and the detonator, Michelle orders Edith to be the one to drop the smoke canister "in the third chimney counting from the west". Assisted by Yvette, she will do it on the first stroke of midnight and on the sixth stroke, René and monsieur LeClerc will smash the window and get into the room.
During a private meal, Helga informs herr Flick that she has been ordered to dine with the general and that the colonel has been ordered to find musicians for the occasion. He orders her to keep looking for evidence of the blowing up plot and he also says he will keep her under observation during the evening.
At night, the café gang (René, Michelle, LeClerc and Crabtree) all disguise themselves as firemen and go to the chateau, while Edith and Yvette are already there, on the roof. There, Edith asks Yvette if she has had an affair with René, which she also denies - and Edith believes her too. Meanwhile, the general, Helga and the colonel are having dinner. After having finished their soup, the colonel starts complaining about his ulcer and leaves. As the musicians enter, the general goes to open a bottle of champagne. Helga then discovers, that the two gypsies playing are in fact herrs Flick and Von Smallhausen in disguise.
On the roof, Edith and Yvette find the chimneys, but they do not know which is the west. As they hear the gypsy music from one of them, they drop the canister in it, thinking it is Gruber playing (not knowing it is coming from the general's quarters). Meanwhile, Gruber telephones the café, asking to speak with René, whom he wishes to join him for a "night cap". A few seconds later, René barges in through the window and being rather surprised at not finding any smoke in the room. He is soon followed by LeClerc, after which the general barges in and orders Gruber to call for the fire brigade, since there is a fire in his room. Then, the fire alarm goes off.
Fanny: (throwing flower pots at Monsieur Alfonse's hearse) "I am not yet ready to go!"