One sunny Sunday, Berenger and Jean meet at a café. Berenger is unkempt, while Jean wears a neat suit and chastises Berenger for being late. He makes fun of Berenger for wanting to drink so early in the day, especially when Berenger is hung over. Taking issue with Berenger’s clothes, Jean gives him an extra tie, a comb, and a mirror. Jean lists all the ways that Berenger needs to work on his appearance and declares that he’s ashamed to be Berenger’s friend. Desperately, Berenger says that he can’t stand working a normal schedule and needs to drink to relax. Jean insists that everyone has to get used to it. The two discuss where Berenger was last night as a rhinoceros races down the street. Berenger seems to not see it, but the Waitress, the Grocer, the Housewife, the Grocer’s Wife, and Jean all stand and point at it.
A Logician, the Old Gentleman, and the Housewife arrive and remark on the rhinoceros. The rhinoceros sent the Housewife’s basket of groceries flying, so she asks the Logician to hold her cat while she repacks her basket. She leaves. Meanwhile, Jean insists on talking about the rhinoceros, but Berenger isn’t interested. Berenger suggests that it might have come from a zoo or a circus, even though Jean points out that their town has neither. In his anger, Jean accuses Berenger again of being an alcoholic who doesn’t think—and then accuses Berenger of insulting him when Berenger tries to defend himself. Jean stops Berenger from drinking as Daisy arrives at the grocery store next door. Noticing that Berenger likes Daisy, Jean takes the opportunity to tell Berenger to stop drinking. Berenger explains that if he doesn’t drink, he feels terrified.
The Old Gentleman and the Logician return. The Logician introduces the Old Gentleman to syllogisms by giving him the syllogism that if a cat has four paws, and if Isidore and Fricot both have four paws, then Isidore and Fricot are both cats. The Old Gentleman notes that his dog has four paws, so it’s a cat too. The Logician agrees with this but cautions him against abusing logic. As Jean lists changes for Berenger to make, the Logician asks the Old Gentleman to deduce what happens when they subtract two paws from the cats. The Old Gentleman deduces that they could have cats with as many as six or as few as zero paws, but the Logician says that having no paws wouldn’t be just—and logic, he insists, is justice. Another rhinoceros stampedes through town. It kills the Housewife’s cat. The Housewife cries and returns to the café with her cat’s body. The crowd cares for the Housewife while the Old Gentleman and the Logician insist that cats are mortal and the Housewife should’ve expected this.
People wonder if the second rhinoceros was the same as the first, but Jean declares that there were two different rhinoceroses: the first was an Asian rhinoceros with two horns, while the second was an African rhinoceros with one horn. Berenger insists that this is ridiculous since the rhinoceroses were moving too fast to count their horns. Jean insults Berenger by calling him an “Asiatic Mongoloid,” which sparks a discussion of the fact that Asian people are people just like any other. Jean angrily leaves and everyone blames Berenger. Others argue over how many horns the rhinoceros had as Berenger regrets his actions out loud. The Logician leads the group in posing what he says is the correct question—how many rhinoceroses and horns—but agrees that this doesn’t answer for the rhinoceros’s violence. He leaves and the Grocer asks if they’re going to allow rhinoceroses to run down cats. Berenger drinks and decides to better himself later.
The next day, Botard, Dudard, Mr. Papillon, and Daisy arrive at work. Botard loudly insists that the rhinoceros is made up—journalists lie, and the article in the paper doesn’t properly define either “pachyderm” or “cat.” He denounces segregation and church by insulting those who saw the rhinoceros for not working on Sundays. Daisy insists that she saw the rhinoceros, but Botard remains derisive. Berenger sneaks into the office just in time to sign in. He joins the conversation and insists that he saw the rhinoceros, but Botard insinuates that Berenger isn’t a reliable witness since he loves Daisy and is an alcoholic. They debate how many horns the rhinoceros or rhinoceroses have, but Mr. Papillon puts everyone to work. Everyone works until Botard accuses Dudard of being part of a nefarious group behind the rhinoceroses. Mr. Papillon returns from his office to confirm that Mr. Bœuf is out. He threatens to fire Mr. Bœuf. Mrs. Bœuf arrives, flustered and out of breath. She explains that her husband is sick and that a rhinoceros chased her and is waiting at the bottom of the stairs. The rhinoceros promptly demolishes the staircase. Botard admits that he can see it and they note that the rhinoceros has one horn, though they don’t know if it’s Asian or African. Mrs. Bœuf realizes that the rhinoceros is her husband, so Mr. Papillon discusses firing him. Botard threatens to get the union involved. Daisy calls the fire department to get them all out as Mrs. Bœuf leaps down the stairwell and onto her husband’s back. Daisy returns with the news that the fire department is busy with other rhinoceros calls as Botard cryptically insists that he never denied that there were rhinoceroses and threatens to expose the plot. Firemen help everyone out through the window.
Berenger goes to visit Jean, but Jean is sick and doesn’t recognize Berenger’s voice when he knocks. Berenger apologizes for getting upset about the rhinoceroses and being obstinate. Jean coughs and says he feels ill, but he doesn’t know what’s wrong. He says he’s full of energy and begins to perform exercises. Berenger tries to come up with explanations for Jean’s illness and increasingly gravelly voice, but Jean insists that Berenger’s voice is changing. They discover a bump on Jean’s forehead and Jean begins to run back and forth to the bathroom, returning to the bedroom with increasingly green skin. Jean is offended when Berenger notes this and refuses to see a doctor. He leaps away when Berenger notes that his skin is hardening. Jean starts eating a magazine and insists that people disgust him and he’ll run them down. Jean insists that Berenger is drunk and begins to trumpet. They discuss Mr. Bœuf’s transformation and as Jean fans himself with his pajama shirt, he insists that Mr. Bœuf transformed on purpose and that he’s better now. Berenger is shocked and argues that while rhinoceroses may have the right to live their lives, they shouldn’t destroy other people’s lives or things. Jean shouts that he wants to replace morality with the law of the jungle and insists that humanism is dead. He suggests that Berenger is prejudiced because Berenger thinks poorly of the rhinoceroses. Jean charges Berenger and then runs back to the bathroom and turns into a rhinoceros. Outside, Berenger can see other rhinoceroses destroying park benches and though he tries to stand by Jean, he runs screaming.
A few days later, Berenger experiences nightmares as rhinoceroses stampede outside. He wakes when he falls out of bed, checks his bandaged forehead for a bump, and drinks. Dudard visits, though Berenger doesn’t recognize Dudard’s voice. Dudard is concerned for Berenger and confirms that he doesn’t have a bump on his head, but they agree that if a person doesn’t want to knock their head, they won’t. He tries to comfort Berenger as they discuss Jean’s transformation. Dudard encourages Berenger to not think about it and reminds him that people aren’t transforming to spite him. Dudard suggests that Jean may have wanted fresh air, and that rhinoceritis is a disease like any other—and for that matter, Jean was an eccentric, not a normal person. Anxiously, Berenger pours himself a drink and reasons that alcohol helps with epidemics, and that Jean’s sobriety possibly opened him up to rhinoceritis. Dudard points out that when Berenger is well enough to go outside, he’ll see that the rhinoceroses are peaceful and funny, but Berenger insists he can’t see it that way. If this happened somewhere else, he suggests, they’d be able to think about it rationally, but seeing it happen to their neighbors makes it personal. He declares he can’t get used to it, but Dudard insists that Berenger can’t judge people for making choices like this. Dudard admits that Mr. Papillon became a rhinoceros, which Berenger doesn’t find funny at all—he believed that Mr. Papillon had a moral responsibility to not transform. Dudard eats a flower off of Berenger’s houseplant.
Dudard accuses Berenger of being intolerant, and they debate whether or not the rhinoceroses are evil or abnormal. Berenger attempts to use logic, but Dudard trips him up and Berenger ultimately declares that he knows intuitively that the rhinoceroses are bad. Berenger decides to call the Logician, but he looks outside and sees a rhinoceros wearing the Logician’s hat. Dudard decides that since the Logician is a great thinker, he must have thought his transformation through fully. As Berenger shouts out the window, Dudard eats his cigarette and lets Daisy in. Daisy ignores Dudard’s advances, worriedly checks Berenger, and says that Botard is now a rhinoceros—before he transformed, he insisted that they need to move with the times. Berenger is shaken. The three discuss whether or not anyone can do anything about the rhinoceroses as they prepare to eat, but they decide that it’s impossible since everyone knows a rhinoceros and animal rights activists would get involved. Dudard begins to think that he’d like to try out being a rhinoceros as they see the firemen transform into rhinoceroses and demolish the fire station. Daisy invites Dudard to sit and eat, but Dudard becomes anxious, charges the door, and becomes a rhinoceros. Daisy and Berenger can’t pick him out among the crowd of rhinoceroses.
Berenger accuses Daisy of not trying hard enough to stop Dudard, but they admit that they love each other. They kiss, and Daisy cautions Berenger that they can’t control others’ lives. Daisy asks Berenger if he’s been sober today and when he lies that he has, she gives him a single glass. Berenger promises to improve now that they’re together but laments that he can’t stop thinking about Jean’s transformation. He disagrees when Daisy suggests he escape into his own version of reality.
The phone rings. When Berenger picks it up, they hear rhinoceroses trumpeting. The news on the radio is also rhinoceroses. Daisy asks Berenger to unplug the phone, but Berenger refuses, which offends Daisy. They vow to keep each other safe, and Berenger shouts at their rhinoceros neighbors to be quiet. Daisy insists that there’s nothing to do and refuses to have children to regenerate the human race. She says that the rhinoceroses look happy and energetic, while her love with Berenger feels weak. Berenger slaps her, and though they promise to love each other, Daisy hears the rhinoceroses’ song and leaves. Berenger inspects himself, wishes he could grow horns and tough skin, and wonders if he’s even speaking French. He’s ashamed of not being able to transform but declares that he’ll remain a man as he sits down with his brandy.
