The story opens in Paris in January 1871, at the height of the siege, and introduces the main character, Monsieur Morissot, a watchmaker who has enrolled in the National Guard. Morissot, who is bored, hungry, and depressed, is walking along the boulevard when by chance he bumps into an old friend, Monsieur Sauvage, with whom he used to go fishing before the war. The two old friends reminisce over several glasses of absinthe in a café, talking wistfully of the pleasant Sunday afternoons they used to spend fishing on the banks of the Seine before the war. Tipsy from the absinthe, the friends, for want of anything else to do, decide to go fishing in their old spot, and having obtained a laissez-passer from their officer, walk along the river to Argenteuil, a few miles west of the city, in the no man's land between the French and Prussian lines. The two start fishing and when they see the nearby fortress of Mont-Valérien firing at the Prussians, they start discussing the war, which turns into a friendly debate at the end of which they both agree that the war is a tragedy for both France and Prussia, and that as long as there are governments, there will be wars.
At this point, the two friends turn round to see four Prussian soldiers pointing their rifles at them. The two are captured and taken to a nearby deserted restaurant, where a Prussian officer makes them an offer: he explains that he can legally shoot them on the spot as spies, but that he will spare their lives and let them return to Paris if they give him the password they used to get through their own defence lines. The two heroically refuse to give him the password, even when the officer reminds them that their deaths will cripple their families. Realising that they will not give him the password, the officer lines up his men into a firing squad. The two friends shake hands and exchange a tearful farewell before they are executed. The German officer orders their bodies thrown into the river, and