At the Siege of Arras, Carbon De Castel-Jaloux and Le Bret keep watch and discuss the lack of food. Cyrano returns from sending a letter to Roxane, looks at Christian as he sleeps, and goes to write another letter. Cannon fire and drums can be heard, waking the Cadets. They complain about the lack of food, and Carbon asks Cyrano to cheer up the men. He offers clever remarks about the situation, offers to lend out his book—the Iliad—and discusses the Cardinal’s extravagant meals. Then, Cyrano asks Bertrandou to play his fife and describes music.

When the Provencal melody begins, Cyrano describes the forests and other parts of the landscape of Gascoyne. The Cadets become homesick and cry. Then, Cyrano encourages the drummer to play, which rouses the men. Guiche approaches, and the Cadets remark on how he dresses inappropriately for the circumstances, how he is the Cardinal’s nephew, and how he is a fake Gascon. Cyrano encourages them to look busy and happy playing card and dice games while he reads Descartes.

Guiche enters, greets Carbon, and notes that the Cadets don’t like him. Carbon says he will not punish the men at Guiche’s command because he only obeys military orders.