The film opens in the trenches of World War I where Ollie, Stan and the rest of their army company are ready to go 'over the top', but Stan is ordered to stay behind to guard the trench. Stock scenes of fighting are then seen followed by the caption 'Armistice'. Twenty years pass, and Stan is still guarding the post, as shown by the huge pile of bean cans he has accumulated, and the path he has worn pacing back and forth on guard. He is found by accident (after firing on a plane he sees approaching) and is brought home, feted as a hero. Ollie, who has been married for a year to the formidable Mrs. Hardy (Minna Gombell), sees him in a newspaper and visits him in the veterans' home. He finds Stan in a wheelchair, having apparently lost a leg, and invites him home. However, Stan is in fact just resting in another veteran's wheelchair and Ollie only finds out he still has both legs after pushing him around in the chair and then carrying him. Ollie, angrily: "Why didn't you tell me you had two legs?" Stan: "Well, you didn't ask me." They reach Ollie's automobile, which he says belongs to his wife and is 'practically new', but it is boxed in by a dump truck. Stan climbs into the cab to move it and inadvertently operates the dump mechanism, burying the car in sand and leaving only Ollie's head exposed. It is then completely wrecked when Ollie demonstrates the automatic garage door at his home and allows Stan to drive the car in to test it.
In 1915, at the airdrome in France of the Royal Flying Corps' 59th Squadron, Major Brand (Basil Rathbone), the squadron commander, and his adjutant Phipps (Donald Crisp) anxiously await the return of the dawn patrol. Brand is near his breaking point. He has lost 16 pilots in the previous two weeks, nearly all of them young replacements with little training and no combat experience. Brand is ordered to send up tomorrow what amounts to a suicide mission. Captain Courtney (Errol Flynn), leader of A Flight, and his good friend "Scotty" Scott (David Niven) return, but two of the replacements are not so lucky, and another, Hollister, is severely depressed by having witnessed the death of his best friend. The survivors repair to the bar in their mess for drinks and fatalistic revelry. Courtney does his best to console Hollister, but the youngster breaks down in grief.
The married Edith Laurin has a love affair with her husband's best friend. When both men serve together at the front her spouse realises he's cuckolded. Because his old friend is also his comrade who fights at his side again the mutual enemy, Laurin doesn't take action against him. After Laurin has died his friend returns home as a cripple.
After the United States enters World War I in 1917, the limousine carrying Daisy Heath (Margaret Sullavan), a sophisticated Broadway musical theatre star, knocks down Bill Pettigrew (James Stewart), a naive young soldier from Texas. A policeman orders the chauffeur to take Bill back to camp. During the ride, he becomes slightly acquainted with the cynical, but not cold-hearted Daisy.
Based on the autobiographical novella of the same title by Kilian Koll, (Walter Julius Bloem, Jr.), the film is set late in 1918, during the final stages of the First World War. A troop of German infantry are on their way from the Eastern to the Western Front and must change trains in Berlin. After marching through the centre of the city from one station to another, they must wait several hours for their connecting train. The major in command gives strict orders that no one must go into this city full of "deserters, revolutionaries, and defeatists", even though most of the men are from Berlin, but in response to the pleading of Colonel Hartmann (Fritz Kampers), who had saved his life in the trenches, young Lieutenant Prätorius (Rolf Moebius) grants passes on the men's solemn promise to return in time: "I have your word of hono[u]r that you will return and fulfill your duty in this critical hour of the fatherland. The unit is counting on you—and so is Germany." The film follows several of the men, in particular four of different ages and from different milieux. Infantryman Ullrich Hagen (Wilhelm König) is a composer; he visits his music teacher, who will shortly be performing one of his works and begs him to be true to his talent rather than throwing his life away in a futile cause. Colonel Hartmann, who is middle-aged, surprises his young wife, Anna, who has replaced him at his work driving a tram; she begs him to stay with her and their four children rather than returning to a war which is already lost. The third, a young man, after discovering his only relative has died, meets a girl and falls in love for the first time. The fourth, Infantryman Emil Sasse (René Deltgen) is a "leftist intellectual" who was cursing the notion of 'heroic death' and announcing his intention to desert in the opening scenes of the film; he finds his girlfriend Fritzi (Margot Erbst) printing anti-war leaflets. All four, however, resist the temptation to desert. Hagen responds that his works can speak for themselves; the young man considers his companions closer to him than his new love; Sasse finds he no longer likes revolutionaries: "We soldiers are dying for our country while you drink, hold meetings, and make love. ... I have nothing in common with you any more." He fights his way out of the meeting and arrives with a black eye and bruises. Hartmann loses track of time, but his family all pile into a friend's lorry and race the train to the next station; the lieutenant spots the speeding vehicle and all the men are back as they promised.
Luciano Serra, valeureux aviateur lors de la Première Guerre mondiale, se retrouve désormais sans but. Il gagne quelque argent en assurant, à l'aide d'un modeste hydravion, le baptême de l'air de touristes en mal de sensations. En 1921, il s'embarque alors pour l'Amérique du Sud, espérant y faire fortune. Là-bas, des financiers lui proposent d'organiser un raid aérien au-dessus de l'Océan Atlantique de Rio de Janeiro à Rome. Trahi par des commanditaires sans scrupules, Luciano n'abandonne pas l'entreprise mais, il disparaît, à bord de son engin, en 1931. Très attaché à l'histoire de son père, Aldo Serra, entre à l'Académie aéronautique de Caserte et participe dès 1935 à la conquête coloniale en Éthiopie. Luciano Serra est, quant à lui, toujours vivant et se retrouve également en Abyssinie. Lors d'une opération dramatique, il sauve son fils, au mépris du danger, mais doit y laisser sa vie.
Le film est divisé en épisodes autour de quatre officiers de l'armée de l'air Fabian, Prank, Moebius et Gerdes, parfois individuellement, parfois ensemble.
Le film dépeint la vie et la mort de Pietro Micca, qui a été tué en 1706 lors du siège de Turin en luttant pour le Duché de Savoie contre le Royaume de France dans la Guerre de Succession d'Espagne.
A hard-working father is called up and sent to the front. He keeps in touch with his family by writing letters home. These include chocolate wrappers collected from his comrades; his son is collecting the wrappers to redeem for a free box of chocolate. The man volunteers for one brave act, joining a suicide squad. Before he goes, he drinks a toast from a cup given him by his son, and (as happens in other "humanist" films) smiles to indicate his intention to die with his comrades. The son receives the news of his father's death at the same time as the free chocolates arrive. He swears vengeance; the chocolate company gives him a scholarship.