The story is set in France in 1809. Captain Neuville (Dujardin) proposes to Pauline Beaugrand. Pauline and her parents gleefully accept, but her sister Élisabeth (Laurent) is worried, because she thinks that Neuville is insincere. The wedding cannot take place, because Neuville must go to fight in a war against Austria. He promises Pauline that he will write to her every day. Time passes, but Pauline does not receive any letter. She is so depressed that Élisabeth starts writing letters that she signs with the name of Neuville, in order to cheer her sister up.
After a period of three years or so, the long missing Capt. Neuville turns up — a dirty, smelly bum, who deserted from the army. A shocked Élisabeth, who sees him in the marketplace, hustles him on a carriage out of town, but not before she tells him about her deceptions. He surprises her by returning again, dressed in a gentleman's clothes, playing the part of the dashing cavalier that Élisabeth invented for him. Élisabeth realizes that she can't tell on him without revealing that she faked his letters for years.
Return of the Hero provides examples of:
- Beard of Sorrow: When Neuville comes back to the village, he has become a tramp and he sports a long beard.
- Belligerent Sexual Tension: Neuville and Élisabeth constantly bicker with each other. In the end, they realize that they love each other and they get married.
- Book-Ends: In the beginning, Neuville must go to war. He promises Pauline that he will write to her every day. In the end, he must go to war again. He promises Élisabeth that he will write to her every day.
- Call-Back: Neuville tells a ridiculous, silly story about how he faced down 2000 British soldiers alone. Later he tells a far more serious and dramatic story about his experience at the Battle of Essling, revealing that he drew the details of his silly story from a ghastly French defeat in which most of his unit was wiped out.
- The Casanova: Neuville takes advantage from the fact that he is considered as a hero to seduce many women, including his ex Pauline and the wife of Mr. Dunoyer.
- The Cavalry:
- Discussed Trope. Neuville makes up a story where he is alone in front of thousands of English soldiers. He is saved at the last moment by the cavalry. Élisabeth criticizes Neuville for using this trope. She thinks that it sounds like a dime-store novel.
- The same happens for real in the end: Neuville is alone in front of the Cossacks' army. At the last moment, the French army shows up and saves him.
- Con Man: Neuville pretends to be a war hero. He pretends to own a diamond mine. He accepts money from people who wants to invest in the mine that does not exist.
- Conversation Cut: One scene cuts back and forth from Élisabeth creating a tall tale of Capt. Neuville's heroism, to the real Neuville telling the story in various settings.
- Covert Pervert: Surprise, surprise, sweet little Pauline is not nearly as innocent as she looks. She writes Neuville a sex letter after he leaves, shocking her sister after Élisabeth intercepts it. Later she's revealed to be a covert masochist who likes getting slapped. Neuville finds this out when they have their rendezvous in the hunting lodge.Pauline: Punish me!
Pauline: Claw me! Harder! Like a tiger! Slap me!
- Defrosting Ice Queen: Élisabeth is single. She tells Neuville that being single is a choice. In the end, she realizes that she loves Neuville and she gets married with him.
- Dirty Coward: Neuville deserted from the French army. At some point, Élisabeth tells him that he disgusts her because he is such a coward. Subverted, because in the end he confronts the Cossacks' army alone. Double Subverted, because in the end, he deserts again.
- Dramatic Drop:
- Élisabeth drops some crockery when she finds out that Capt. Neuville has returned. The twist in this case is that she has already found out that he's alive, but she thought she'd successfully gotten him out of town.
- She does this again near the end when, instead of confessing all to her family, Neuville asks them for her hand in marriage.
- Dramatic Sit-Down: Nicolas sits down on his model ship, crushing it, after reading Pauline's sex letter to Neuville that Élisabeth arranged for him to find.
- Duel to the Death: Nicolas hears that his wife Pauline has an affair with Neuville. He challenges Neuville to a duel. The duel is interrupted by Pauline.
- Erotic Eating: Their sex life having been hugely improved by getting into BDSM, near the end Nicolas is feeding Pauline chocolates by hand.
- Fake Ultimate Hero: Neuville claims to be the hero that Élisabeth described in letters, even if he actually deserted from the French army. Subverted, because in the end he confronts the Cossacks' army alone.
- Gray Rain of Depression: A despondent Pauline goes wandering out in the rain after months with no word from Neuville. Naturally she gets pneumonia, which is why Élisabeth writes the letters, to give her something to live for.
- Happily Ever After: Élisabeth and Neuville get married in the end.
- Hit Me, Dammit!: It turns out that Pauline is a Covert Pervert who's really, really into getting slapped and hit. Neuville is pretty badly startled when their literal roll in the hay turns into this, and later, after Pauline and her husband find happiness in BDSM, she asks him to do this regularly.
- Improbable Infant Survival: Discussed Trope. In a letter, Élisabeth writes that Neuville saved several children from drowning, but failed to save one of them. Élisabeth tells that she thought that it was more realistic to let one child die. Neuville is not happy with that and later he tells everybody that finally the child survived.
- Jabba Table Manners: Neuville's status as a smelly hobo upon his return is underlined when he steals a fish in the marketplace, and simply bites a huge chunk out and eats it, skin, bones and all.
- Jerk-to-Nice-Guy Plot: Neuville is a Con Man and a Dirty Coward. When the Cossacks attack the château, he shows that he can be really brave: he confronts them alone. Subverted because in the end he deserts again.
- Ponzi: Neuville accepts money from several people. He pretends to invest it in a diamond mine that does not exist. He pays the investors back with the money new investors give to him.Neuville: I've designed what you could call a pyramid scheme.
- Right Through the Wall: Élisabeth is extremely irritated by the loud sex coming from Nicolas and Pauline's room, especially with Pauline begging her husband to slap her.
- Romanticized Abuse: Tied in with Covert Pervert. Pauline interrupts the Duel to the Death between Nicolas and Neuville, but then she gets angry and starts ranting to Nicolas about how he's thoughtless and weak and his feet stink. At a hint from Neuville who knows about her masochistic tendencies, Nicolas slaps Pauline across the face. They walk off together hand-in-hand, with Pauline clearly turned on.
- Sex with the Ex: During the ball, Neuville and Pauline, his ex, agree to have sex together. Subverted because Élisabeth prevents them twice from doing so.
- Shout-Out: The inn from which smelly tramp Neuville is thrown out is called "Le Rieur Sanglier", as in Asterix in Britain.
- Snowball Lie: Élisabeth writes letters that she signs with the name of Neuville. According to these letters, Neuville is a real hero, whereas in reality he is a deserter. When Neuville comes back, he realizes that everybody in the village considers that he is a hero and that he can take advantage of it, so he pretends to be a hero. Finally, Élisabeth tries to tell the truth about Neuville and the letters, but nobody believes her.
- Voiceover Letter: Played for a gag, when Élisabeth forges Neuville's letters but they are still read in voiceover with his voice.
- White Stallion: Capt. Neuville makes his dramatic return, pretending to be a conquering hero, riding up to the mansion on a beautiful white horse.