Act I

The military encampment.

In 1720, or thereabouts, in the Grand Duchy of Gerolstein there is going to be war. In the camp, a small but enthusiastic army awaits its departure for this war which is to be fought against an unnamed enemy. We see soldiers, peasant girls, camp-followers, and a young couple: Fritz, a soldier, and Wanda, his betrothed. They are drinking, perhaps draining their last glass together, and dancing, spinning 'like tops' to give them a good send-off. But pif ,paf, pouf. here comes General Boum, 'á cheval sur la discipline' ['a stickler for discipline']. The women flee. Tara papa poum, the general gets angry at Fritz's insolence. An aide-de-camp announces that the Grand Duchess will shortly be arriving. Boum orders Fritz to stand guard, and leaves the camp with his army. Despite the order forbidding him to move, Fritz kisses Wanda, once, twice... The general returns: his large-scale troop-movement was just intended to catch the young soldier out. At the sound of cannon, Fritz and Wanda run off, just as Baron Puck enters. Baron Puck and General Boum are conspiring together. They have a single aim: to stay in power. But the Grand Duchess, with nothing to do, is bored; so, to amuse her, Puck has had war declared and is also trying to find a husband for her: Prince Paul. But the Grand Duchess doesn't want him, and Puck and Boum are worried: 'si Son Altesse s'avisait d'avoir un favori!' ['What if Her Highness decided to take a favourite!']

The Grand Duchess arrives. It's another of Puck's ideas: she is here to 'encourage' the soldiers by singing the regimental song with the general. But the ruler, who 'aime les militaires' ['loves soldiers'], gives Fritz a big shock; from being a private soldier, in a trice he climbs through the ranks. She makes him a captain - a staggering promotion!-and sings the regimental song with him. Still better is to come: after studying General Boum's non-aggressive plan of attack, she chooses the tactics recommended by the new captain and names him general and head of the army. She entrusts to him her father's sabre, and Fritz takes leave of Wanda, going off to battle as a future conquering hero.

Act II

A room in the Grand Duchess's palace

The war is over. The soldiers return; Fritz is victorious - The Grand Duchess is refusing to receive Baron Grog, the ambassador of Prince Paul's father, who wants to conclude the marriage; she is happily waiting for Fritz. But history is about to repeat itself. The Grand Duchess's grandmother, Victorine, once had a lover, Max, who was a soldier. Every evening he used to go down a secret corridor, hidden behind a picture at each end, to get to her room, and one night Max was assassinated. This is the fate which awaits Fritz. Boum, Puck and Paul conspire - in deadly earnest.

The great general makes his triumphal entry and recounts his heroic four-day battle. He got the opposing army so drunk they couldn't fight. The Grand Duchess, herself intoxicated with love, dismisses the court and is alone with her conqueror. She offers him rewards 'dans le civil' ['in civilian life'], telling him that from now on he is to live in the palace. Fritz has no idea what she is getting at. Then the Duchess has the idea of telling him about a lady, a friend of hers, who is in love with him - Fritz laughs at this, having no idea what she means. Moreover, he can't pursue it; he loves Wanda. She must tell the lady this. He asks the Grand Duchess to be a signatory to his marriage contract - This is the last straw, and the scorned ruler joins the conspirators' camp. Yes, Fritz must die! She might give the signal by having them do the dance of the 'carillon de sa grand-mére' ['her grandmother's carillon'] at the ball this evening. The notary arrives, and Fritz marries Wanda. The Grand Duchess chokes with anger, and gives the signal: the carillon strikes up.

Act III

Victorine's red boudoir

The Grand Duchess muses about the past, about her 'charmant petit naturel' ['charming little disposition'], and about the present, with love affairs and murders vying for her attention. The conspirators, seventeen of them, arrive, sharpening their knives. Everything is ready. However, when she sees Baron Grog, the Duchess regrets not having received him: he is so handsome! She is left alone with him and suggests he quit the court of Prince Paul: he would do better at her establishment. Baron Grog refuses, ...but if she were to marry the prince..., Delighted, the Grand Duchess accepts. She will get married and no one will get killed. She tells the prince, who is overcome with joy. However, Boum and Puck are furious, and still want vengeance on Fritz. The Grand Duchess accepts this: vengeance, yes, but no killing. So instead, they upset Fritz's and Wanda's wedding night by sending the general off on horseback to fight quite another kind of battle.

The military encampment

In camp there is drinking again, this time to celebrate the royal wedding. The Grand Duchess joins the festivities and is astonished by the absence of General Fritz. Boum explains; he sent General Fritz off on a Pavlovian horse which automatically gallops to the house of a lady whom General Boum himself used to visit but the husband got suspicious. Fritz returns beaten up, with 'le sabre de papa' all bent. So the Grand Duchess relieves him of all his ranks and honours, but when she tries to bestow all these distinctions on Grog, the chamberlain tells her that he has three children, soon to be four. The Grand Duchess, her ardour cooled by this, sends him back to the court he came from and decides that after all that 'puisque' elles ne peut pas avoir ce quelle aimer, 'd'aimer ce quelle a' ['since she can't have what she loves, she will love what she has']