Village landowners Prostakov. Madam Prostakova in anger: the serf tailor Trishka, she believes, sewed a too narrow caftan to her beloved son, sixteen-year-old undergrowth Mitrofanushka. Trishka justifies herself by not studying tailoring, but the lady doesn’t want to listen to anything. Her husband, Prostakov, a near and obedient wife, expresses the opinion that the caftan is baggy. And to Taras Skotinin, Prostakova’s brother, it seems that the caftan is “well-made”.

The caftan itself is a new thing to Mitrofanushka for the conspiracy of Skotinin with Sophia, a distant relative of the Prostakovs. Sophia's father died when she was still a baby. The girl grew up with her mother in Moscow. But six months have passed already, when she remained an orphan. The simpletons took her to themselves in order to "oversee her estate, as her own." Uncle Sophia, Starodum, went to Siberia. For a long time there was no news of him, and the Prostakovs believe that he died long ago.

Skotinin wants to marry Sophia - not because he likes the girl, not because he wants to take possession of her villages, but because there are many ... pigs in these villages, and he is a big hunter before them. And Sophia still doesn’t know whom they are reading to her husbands.

Sophia receives a letter from Starodum. Madam Prostakova, hearing about this, is extremely annoyed: her hopes did not come true, her uncle was alive. Prostakova accuses Sophia of lying: a letter, they say, amorous. But she cannot verify the statement, for she is illiterate. Her husband and brother are not much to read either. They are rescued by guest Pravdin. He reads a letter in which Starodum informs his niece, which makes her the heir to his fortune, acquired by him in Siberia, which gives an income of ten thousand a year. Mrs. Prostakova is struck by this news. She has a new idea: to give Sophia for her son, ignoramus Mitrofan.

Soldiers pass through the village of Prostakovs. They are led by officer Milon. Here he meets his old friend, Pravdin. He says that he is a member of the governorship. Pravdin goes around the district and especially draws attention to “malevolent ignoramuses” who mistreat their people. It was such ignoramuses that he found in the person of the Prostakovs.

Milon, on the other hand, says that he is in love and has been separated from his beloved for more than six months. Recently, he found out that his beloved was left an orphan and some distant relatives took her to their villages ... At the moment when Milon speaks about this, he suddenly sees his beloved - this is Sophia.

Lovers are glad to meet. But Sophia says that Mrs. Prostakova wants to marry her to Mitrofanushka. Milon is tormented by jealousy. True, she weakens when he finds out more about his "rival".

Skotinin passing by unceremoniously declares his views on Sophia. Pravdin tells him about the plans of Mrs. Prostakova. Skotinin is furious. Mitrofan catches his eye, whom the nanny Yeremeyevna leads to study. Uncle wants to explain to his nephew and was already attacking him with his fists. But Yeremeyevna overshadows Mitrofanushka and drives away Skotinin.

Teachers of Mitrofanushka come: Sidorych - Kuteikin and Pafnutich - Tsyfirkin. Kuteikin, the deacon from the Intercession, who had not yet studied at the seminary, teaches Mitrofan literacy in the Book of Psalms and the Psalms. And Tsyfirkin, a retired sergeant, is a teacher of arithmetic.

Mitrofan refuses to study. He complains to his mother that after Uncle’s "task" learning doesn’t come to his mind. Eremeevna talks about a clash with Skotinin. Prostakova consoles her son, promises to marry him soon. She tells the teachers to feed them lunch and send them again. Madame is unhappy with Yeremeyevna: she "did not dig into a mug" to Skotinin and "did not rip the snout to his ears." Prostakova is going to "transfer" with her brother in her own way. Zealous Eremeevna cries from resentment. Teachers console her.

Starodum arrives. Before appearing to the owners, he talks with an old acquaintance, Pravdin. Starodum recalls his father, who served Peter the Great, praises those times. Starodum came to free his niece from "ignoramuses without a soul." He was forced to leave the civil service. When Starodum still served in the military, he became friends with the young count. Upon declaring war, Starodum hastened into the army, and the count avoided this. And soon after this, the count was made a rank, and Starodum, wounded in the war, was circumvented. Having retired, Starodum came to Petersburg to the court. But later he decided that "it is better to lead a life at home than in someone else's front."

Starodum meets with Sophia and promises to take her niece away from the Prostaks. The conversation was interrupted by the appearance of Prostakova and Skotinin. Sister and brother fight, and Milon undoes them. Staroduma, this scene is amusing. Mrs. Prostakova is annoyed by the stranger's amusement, but, having learned that this is Starodum, she changes her tone to the most servile and obliging. She wants to seduce a wealthy relative and contribute to this marriage of Mitrofanushka to Sophia.

But Starodum promises to bring Sophia to Moscow the next morning to marry her there to a certain "young man of great virtues." This news plunges everyone into discouragement, and Sophia "seems struck." Then Starodum tells her that choosing a worthy groom is entirely in her will. This brings hope back to everyone. Mrs. Prostakova boasts to Starodum about the formation of Mitrofanushka. She is especially pleased with the German Adam Adamic Vralman, whom she hired for five years. She pays him three hundred rubles a year (to other teachers - ten). Vralman teaches Mitrofan "in French and all sciences." But the main thing is that he "does not captive the child."

Meanwhile, Kuteikin and Tsyfirkin are sad that the teaching is not very successful. Mitrofan has been studying arithmetic for the third year, but “cannot count three”. He is studying the letter for the fourth year, and until now he "will not make out the new line." And the whole trouble is that Vralman indulges a lazy student and interferes with his studies.

Mrs. Prostakova persuades her son to learn. He demands that as soon as possible there is a conspiracy: "I do not want to study, I want to get married." Tsyfirkin sets two tasks for Mitrofan. But the mother intervenes and does not allow them to be resolved. In general, arithmetic seems to her an empty science: “There is no money - what to consider? There is money - we’ll consider it well without Pafnutich. ” Tsyfirkin has to finish the lesson. His place is replaced by Kuteikin. Mitrofan is meaninglessly repeating the lines from the Hourglass. Then Vralman appears. He explains to Mrs. Prostakova that it is very dangerous to stuff your head too much. Vralman believes that you can do without Russian literacy, and without arithmetic. Mitrofanushka, he says, only needs to know how to live in the light. Vralman releases Mitrofan to frolic.

Tsyfirkin and Kuteykin want to beat Vralman. The retired sergeant swings the board, and the clerk swings the Hourly Book, but the German manages to escape.

Sophia reads a book by Fenelon on the education of girls. Starodum talks with her about virtue. He receives a letter from Count Chestan. This is Uncle Milon, who wants to marry his nephew to Sophia. Talking with Sophia about her marriage, Starodum again notes that she is embarrassed ... Then Pravdin and Milon appear. Pravdin represents Milon Staroduma. It turns out that Milon in Moscow often visited the house of Sofya’s mother, and she loved him as a son. Starodum, talking with Milon, is convinced that he is dealing with a worthy person. Milon asks for Sophia’s hands, mentioning his “mutual inclination” with the girl. Starodum gladly learns that Sophia chose the one whom he himself read to her husband. He agrees to this marriage.

But the other pretenders to Sophia’s hand know nothing and do not abandon their hopes. Skotinin starts talking about the antiquity of a kind. Starodum jokingly pretends that he agrees with him in everything. Mrs. Prostakova offers Starodum to see how Mitrofanushka is learned. Sofin's uncle portrays as if in awe of Mitrofanushkina scholarship. However, he refuses both Skotinin and Mitrofanushka, saying that Sophia has already been conspired. He announces that he will leave with Sophia at seven in the morning. But Mrs. Prostakova decides that before this time she will have time to "put on her own." She puts the sentries around the house.

Pravdin receives the package; he was ordered to take custody of the house and villages of the Prostakovs on the very first occasion, when Prostakova’s temper would threaten the safety of her subjects. Pravdin tells Starodum about this. Their conversation is interrupted by noise ...

The people of Prostakova drag Sophia, who is resisting, to the carriage - to marry Mitrofanushka. Milon, who caused this scene, frees the bride. Pravdin threatens that Prostakova will appear before the court as "a violator of civil peace." Mrs. Prostakova violently repents of her act. Starodum and Sophia forgive her. Prostakova glad for forgiveness: now she will avenge her servants for the failure! But she does not succeed in doing this: Pravdin announces that by government decree he takes custody of the house and villages of the Prostakovs.

Skotinin podobru-pozdorova leaves for his beloved stables. Mrs. Prostakova asks Pravdin to give her power for at least three days. But he does not agree. He calls for teachers to settle accounts with them. Yeremeyevna leads Kuteikin, Tsyfirkin and Vralman. Pravdin lets them go home. Kuteikin demands that he be paid for his studies, for his worn boots ... But Tsyfirkin refuses to pay, because Mitrofanushka has learned nothing. For such generosity, Starodum, Milon and Pravdin give him money. And Kuteikin Pravdin offers to settle accounts with the lady herself. He exclaims in horror: "I am retreating from everything." In Vralman, Starodum recognizes his former coachman. It turns out that Vralman could not find a coachman anywhere and had to go to the teacher. Starodum agrees again to take him to his coachman.

Starodum, Sophia and Milon are about to leave. Prostakova hugs Mitrofanushka: “You are the only one left with me ...” But her son is rude to her. Mother faints. Pravdin decides to send Mitrofan to the service. When she woke up, Madame Prostakova lamented: “I have completely died ...” And Starodum, pointing to her, says: “Here are evil deeds worthy of fruit!”