Your true self has prevailed over your outer appearance. I now love you for your soul alone.
At the siege of Arras, the Cadets of Carbon de Castel-Jaloux languish, surrounded by the encamped Spaniards and lacking food and water. Le Bret keeps watch with Carbon early one morning, and they discuss the plight of the soldiers. They hear gunfire in the distance, and Cyrano runs in. Every morning he has been crossing enemy lines to post a daily letter to Roxane. Cyrano tells the startled guards that he promised Roxane that Christian would write her every single day. Cyrano looks at the sleeping Christian and says that Christian is dying of hunger but is still handsome.
Dawn breaks, drums sound, and Cyrano goes off to write another letter. The cadets awaken and complain about their hunger. There is talk of a mutiny, and Carbon asks Cyrano for his help.
Cyrano comes out and talks to the cadets, restoring morale with a clever speech and his passionate commitment to the cause. He implores a piper to play a song from Provence, and though the cadets become tearfully homesick, they do forget about their hunger. De Guiche enters, evoking a general murmur of resentment from the cadets. Cyrano tells the miserable cadets to stop moping and to look busy as de Guiche arrives.
Prompted by Cyrano, de Guiche boasts of his conduct in the previous day’s battle when, to confuse the Spaniards, he flung away the white plume that marked him as an officer. Cyrano then proclaims that a courageous man would never have flung away the white plume, and he offers to wear it in the next bout of fighting. De Guiche says Cyrano makes the pledge only because he knows the plume lies somewhere on the battlefield. To the cadets’ delight, Cyrano produces the plume from his pocket.
Furious, de Guiche seizes the plume and waves it to a sentry, who runs toward the Spanish encampments. De Guiche says that he has just given a signal and that the Spanish will attack in perhaps an hour. He says that the cadets will all die but that, in the process, they will buy the French forces as much time as possible. Cyrano thanks de Guiche solemnly for the opportunity to die with glory.
Christian tells Cyrano he wishes he could say farewell to Roxane, and Cyrano shows him the farewell letter he has just written. Christian notices the mark of a tear on the letter and nearly guesses Cyrano’s secret. He is interrupted by the arrival of a mysterious coach.