The curtain rises to show the interior of a theater. Several spectators are present, waiting for the play to begin, and their conversation informs us (erroneously) that this is the famous theater in which Corneille’s Le Cid was introduced. The play tonight is Baro’s Clorise, and the leading actor is Montfleury.
Ragueneau and Le Bret enter, and Ligniere calls attention to the fashionable people who are present. They wonder where Cyrano is, since he has forbidden Montfleury to act on the stage. When Roxane enters, Christian points her out to Le Bret as the woman with whom he is in love, even though he does not know her name and has never talked to her. Ligniere says that De Guiche is also interested in Roxane, and though she is resisting him, he is a very powerful and vindictive man. He is also married.
Before the play-within-a-play begins, Christian goes to warn Ligniere (who has left the theater) that his latest poem has offended a highly placed person who has stationed a hundred men near Ligniere’s street to ambush and murder him.
The curtain rises and Montfleury enters on stage. As he begins to speak, Cyrano’s voice interrupts and tells him to leave the stage. Cyrano offers to fight anyone who wishes to defend Montfleury, but there are no volunteers. When the manager of the theater asks Cyrano if he is also going to force him to refund the money of the patrons, Cyrano tosses a bag of gold to the stage, and the manager is happy.
An affected gentleman who wishes to insult Cyrano says, “Your nose is very large.” Cyrano describes to him what a number of different types of people might have said about his nose. Then he says that while they duel, he will compose a ballade and thrust on the last line. He proceeds to do just that.
When almost all the spectators have left the theater, Cyrano confesses to Le Bret that he is in love with his cousin, Roxane. Then Roxane’s duenna, or female chaperon, comes in and makes an appointment with Cyrano for the next day. He is ecstatic, and when he learns of Ligniere’s plight, he happily goes off to fight the one hundred men lying in wait for the poet.
The next morning, Cyrano waits for Roxane in Ragueneau’s pastry shop. He writes a letter, thinking that he may simply hand it to her when she arrives and leave without waiting for her answer. When she comes, she confesses that she is in love with Christian. Cyrano, broken-hearted though he is, promises that he will look after Christian for her. All of Paris is talking of his exploit of the previous night in routing the one hundred men sent to murder Ligniere. De Guiche comes and offers to be Cyrano’s patron, but Cyrano refuses.
Christian joins the Cadets of Gascogne, the famed Gascony Guards, and he and Cyrano become friends. He confesses to Cyrano that he loves Roxane, but that he is afraid that he cannot express himself well enough to win her love. Cyrano gives him the letter that he himself had written to Roxane and tells him to send it to her in his own name. This is the beginning of the deception. Cyrano writes beautiful letters and makes up impassioned speeches that Christian memorizes. Roxane falls in love with Christian’s borrowed eloquence.
At last, however, Christian tires of his role as Cyrano’s mouthpiece. The company is leaving for the siege of Arras, and before he goes, he wants to woo Roxane with his own words. But he has underestimated the strength of her attachment to beautiful language and gets nowhere with her. Cyrano saves the day for him by hiding under the balcony where Roxane stands and whispering words that Christian repeats. Soon, however, Cyrano’s enthusiasm makes this unbearable and he speaks aloud — but Roxane does not know that it is he and not Christian who is speaking.
A monk brings a letter from De Guiche to Roxane, saying that he is sending the regiment on ahead, but that he is remaining behind for one night in the expectation of meeting Roxane secretly. Roxane pretends that the letter directs the monk to marry her to Christian immediately, which he does while Cyrano detains De Guiche. The marriage is not consummated, however, because the Guards leave for the front, on the orders of De Guiche, to fight at the siege of Arras.
During the siege, Cyrano finds a way through the lines and risks his life to get letters to Roxane, purportedly from Christian. Much to the surprise of everyone, Roxane appears, bringing food and news, which makes Cyrano’s hopes soar. She has come, she says, to confess that at first she loved Christian for his beauty, but that now, because of his letters, she has fallen in love with his spirit and his wonderful mind. This is a much deeper and truer love, and she is ashamed that she has been so shallow.
Christian is an honorable man and he wants Cyrano to tell Roxane the truth. Just as Cyrano is about to do so, Christian’s body is carried in; he has been killed by the first shot fired in the battle.
Nearly 15 years elapse, and we find the mourning Roxane in a convent. She has always carried Christian’s last letter next to her heart. Cyrano comes to her each week and gives her a witty resume of the week’s gossip. Today, however, he is late. One of Cyrano’s enemies has managed to injure him by having a lackey drop a heavy log on Cyrano’s head as he passed beneath a window. Cyrano is mortally wounded, but still comes just at sunset, as always, to give Roxane her news of the outside world. He sits in his usual chair and begins, but then asks to read Christian’s last letter. Roxane gives it to him. As he reads, she realizes that it is too dark for him to see the words and that this was the voice she had heard under her balcony on her wedding night. As Cyrano dies, Roxane says that she has loved only once, but has lost her love twice.