Area in a provincial town. The shopkeeper hisses indignantly after the woman with the cat - The housewife went shopping in another store. Jean and Beranger appear almost simultaneously - nevertheless, Jean reproaches a friend for being late. Both sit at a table in front of the cafe. Beranger doesn’t look good: she can hardly stand, yawns, the suit is dented, her shirt is dirty, her shoes are not cleaned. Jean enthusiastically lists all these details - he is clearly ashamed of a limp friend. Suddenly you hear the clatter of a running huge beast, and then a long roar. The waitress screams in horror - it's a rhino! A startled housewife runs in, frantically clutching a cat to her chest. An elegantly dressed Old gentleman is hiding in the shop, unceremoniously pushing the owner. The logician in the boater hat is pressed against the wall of the house. When the stomp and roar of a rhino subside in the distance, everyone gradually comes to their senses. The logician states that a rational person should not succumb to fear. The shopkeeper is insinuatingly comforting the Homemaker, praising her goods at the same time. Jean is indignant: a wild animal on the streets of the city is unheard of! Only Beranger was inhibited and languid with a hangover, but when he saw the young blonde Daisy, he jumps up, knocking over his glass to Jean's trousers. Meanwhile, the Logic is trying to explain to the Old Master the nature of the syllogism: all cats are mortal, Socrates is mortal, therefore, Socrates is a cat. Shocked, Old Master says that his cat's name is Socrates. Jean tries to explain the essence of the correct lifestyle to Beranger: you need to arm yourself with patience, intelligence and, of course, completely give up alcohol - in addition, you need to shave every day, thoroughly clean your shoes, walk in a fresh shirt and a decent suit. Shocked Beranger says that today he will visit the city museum, and in the evening he will go to the theater to watch the play of Ionesco, which is now widely discussed. The Logic approves of the first successes of the Old Master in the field of mental activity. Jean welcomes Beranger's good impulses in the field of cultural leisure. But here all four are drowned out by a terrible hum. Exclamation “Oh, rhino!” is repeated by all the participants in the scene, and only Beranger breaks out the cry "oh, Daisy!" Then a heartbreaking meow is heard, and the Housewife with a dead cat in her arms appears. An exclamation “Ah, poor pussy!” Is heard from all sides, and then the debate begins about how many rhinos were. Jean states that the first was Asian with two horns, and the second African with one. Beranger, unexpectedly for himself, objects to his friend: the dust was a pillar, there was nothing to see, and even more so to count the horns. Under the lament of the Housewife, the skirmish ends in a quarrel: Jean calls Beranger a drunkard and announces a complete breakdown. The discussion continues: the shopkeeper claims that only the African rhino has two horns. The logician proves that the same creature cannot be born in two different places. Upset Beranger scolds himself for his incontinence - there was no need to climb on the rampage and anger Jean! Having ordered a double portion of cognac with grief, he cowardly refuses his intention to go to the museum.

Law office. Beranger’s colleagues are vigorously discussing the latest news. Daisy says she saw the rhino with her own eyes, and Dudar shows a note in the incident department. Botar claims that all these are stupid tales, and a serious girl doesn’t want to repeat them - being a man of progressive beliefs, he does not trust corrupt newspaper people who write about some crushed cat instead of exposing racism and ignorance. Beranger appears, who, as usual, is late for work.The head of the office, Papillon, urges everyone to take up the matter, but Botar can’t calm down: he accuses Dudar of malicious propaganda with the aim of escalating mass psychosis. Suddenly, Papillon notices the absence of one of the employees - Beth. A frightened Madame Beth runs in: she reports that her husband was ill, and a rhino was chasing her from the house. Under the weight of the beast, the wooden staircase collapses. Crowding upstairs, everyone looks at the rhino. Botar claims that this is a dirty fraud of the authorities, and Madame Beef suddenly cries out - she recognizes her husband in a pachyderm animal. He answers her with a frantically gentle roar. Madame Beth jumps on his back, and the rhino gallops galloping home. Daisy calls firefighters to evacuate the office. It turns out that firefighters are in great demand today: there are already seventeen rhinos in the city, and rumored to be thirty-two. Botar threatens that he will expose the traitors responsible for this provocation. A fire truck arrives: employees go down the rescue ladder. Dudar suggests Beranger tug on a glass, but he refuses: he wants to visit Jean and, if possible, make peace with him.

Jean's apartment: he is lying on the bed, not responding to the sound of Beranger. The old neighbor explains that yesterday Jean was very out of sorts. Finally, Jean admits Beranger, but then again lies down in bed. Beranger, stammering, apologizes for yesterday. Jean is clearly sick: he speaks in a hoarse voice, breathes heavily, and listens with growing irritation to Beranger. The news of Bef turning into a rhinoceros finally infuriates him - he begins to rush about, hiding in the bathroom from time to time. From his increasingly slurred cries, one can understand that nature is higher than morality - people need to return to primitive purity. Beranger notices with horror how his friend gradually turns green and a lump similar to a horn grows on his forehead. Once again running into the bathroom, Jean begins to roar - no doubt, this is a rhino! With difficulty closing the angry beast with a key, Beranger calls for help from a neighbor, but instead of the old man he sees another rhino. And outside the window, a whole herd destroys the boulevard benches. The bathroom door bursts and Beranger takes flight with a desperate cry: "Rhinos!"

Beranger’s apartment: he lies on a bed with his head tied. From the street there is a clatter and roar. There is a knock on the door — it was Dudar who came to visit a colleague. Lucky health questions terrify Beranger - he constantly imagines that a lump grows on his head and his voice becomes hoarse. Dudar is trying to reassure him: in fact, there is nothing terrible in turning into a rhinoceros - in fact, they are not evil at all, and they have some kind of natural simplicity. Many decent people completely disinterestedly agreed to become rhinos - for example, Papillon. True, Botar condemned him for apostasy, but this was dictated more by hatred of the authorities than by genuine convictions. Beranger rejoices that there are still unbending people - if only we could find the Logic who will be able to explain the nature of this madness! It turns out that the Logic has already turned into a beast - it can be recognized by the boater hat pierced by the horn. Beranger is depressed: at first, Jean is such a bright person, champion of humanism and a healthy lifestyle, and now Logic! Daisy appears with the news that Botar has become a rhino - according to him, he wished to keep up with the times. Beranger declares that it is necessary to combat brutality - for example, to place rhinos in special pens. Dudar and Daisy unanimously object: the animal welfare society will be against it, and besides, everyone has friends and close relatives among the rhinos. Dudar, clearly upset that Daisy prefers Beranger, makes a sudden decision to become a rhino. Beranger tries in vain to dissuade him: Dudar leaves, and Daisy, looking out the window, says that he has already joined the herd. Beranger realizes that Daisy's love could save Dudar.Now there are only two of them left, and they must protect each other. Daisy is scared: a roar is heard from the telephone receiver, a roar is transmitted on the radio, the floors walk with a shake due to the stomp of rhino residents. Gradually, the roar becomes more melodic, and Daisy suddenly declares that the rhinos are well done - they are so funny, energetic, it's nice to look at them! Beranger, unable to restrain herself, gives her a slap in the face, and Daisy leaves for the beautiful musical rhinos. Beranger with horror looks at himself in the mirror - how ugly a human face! If he could grow a horn, acquire a skin of wonderful dark green color, learn to roar! But the last man can only defend himself, and Beranger looks around in search of a gun. He does not give up.