The main events take place in the hostel "mother" Voke. At the end of November 1819, seven permanent “parasites” were found here: on the second floor, young lady Victorina Tifer with a distant relative, Madame Couture; on the third, a retired official Poiret and a mysterious middle-aged gentleman named Vautren; on the fourth, the old virgin Mademoiselle Michonault, a former grain trader Gorio and a student Eugene de Rastignac, who came to Paris from Angouleme. All the tenants unitedly despise dad Gorio, who was once called "master": having settled with Mrs. Voke in 1813, he occupied the best room on the second floor - then he obviously had some money, and the mistress hoped to end her widowed existence. She even went into some cost of the common table, but the “Vermicelli” did not appreciate her efforts. The frustrated mother Voke began to glance at him askance, and he fully lived up to bad expectations: two years later he moved to the third floor and stopped drowning in the winter. Vigilant servants and tenants guessed the reason for such a fall very soon: charming young ladies occasionally came to Gorio's dad secretly - obviously, the old lecher promoted a fortune to his mistresses. True, he tried to pass them off as his daughters - an unreasonable lie that only amused everyone. By the end of the third year, Gorio moved to the fourth floor and began to walk in cast-offs.

Meanwhile, the measured life of the Voke house begins to change. Young Rastignac, intoxicated by the brilliance of Paris, decides to penetrate the high society. Of all the rich relatives, Eugene can count only on the Viscountess de Bosean. After sending her a letter of recommendation from his old aunt, he receives an invitation to the ball. The young man wants to get closer to some noble lady, and his attention is attracted by the brilliant Countess Anastazi de Resto. The next day, he talks about it to his co-workers at breakfast, and finds out amazing things: it turns out that the old man Gorio is familiar with the countess and, according to Votren, recently paid her past-due bills to the loan shark Gobsek. From this day, Votren begins to closely monitor all the actions of the young man.

The first attempt to make a secular acquaintance turns into a humiliation for Rastignac: he came to the countess on foot, calling the contemptuous smiles of the servants, did not immediately find the living room, and the mistress of the house made it clear to him that she wanted to be alone with Count Maxim de Tray. Enraged, Rastignac is imbued with wild hatred of an arrogant handsome man and vows to triumph over him. On top of all the troubles, Eugene makes a mistake, mentioning the name of dad Gorio, whom he accidentally saw in the courtyard of the count's house. A dejected young man goes on a visit to the Viscountess de Bosean, but chooses the most inopportune moment for this: his cousin will face a heavy blow - the Marquis d’Ajuda Pinto, whom she passionately loves, intends to part with her for the sake of a profitable marriage. The Duchess de Lange is happy to report this news to her "best friend." The Viscountess hastily changes the subject of the conversation, and the mystery tormenting Rustignac is immediately resolved: Anastasi de Resto, as a girl, bore the name of Gorio. This pathetic man also has a second daughter, Dolphin - the wife of the banker de Nusingen. Both beauties actually renounced the old father, who gave them everything. The Viscountess advises Rastignac to take advantage of the rivalry of two sisters: unlike Countess Anastazi, Baroness Delfin is not taken in high society - this woman will lick all the dirt on the adjacent streets for inviting Viscountess de Bosean to the house.

Returning to the guesthouse, Rastignac announces that from now on he will take Papa Gorio under his protection. He writes a letter to his family, begging to send him a thousand two hundred francs - this is an almost unbearable burden for the family, but the young ambitious man needs to get a fashionable wardrobe. Vautin, who unraveled the plans of Rastignac, invites the young man to pay attention to Quiz Tyfer. The girl vegetates in a guesthouse, because her father does not want to know her - a wealthy banker. She has a brother: it is enough to remove him from the stage so that the situation changes - the Quiz will become the only heiress. Votren takes care of the young Tyfer, and Rastignac will have to pay him two hundred thousand - a mere trifle in comparison with the millionth dowry. The young man is forced to admit that this terrible man rudely said the same thing as the Viscountess de Bosean said. Instinctively sensing the danger of a deal with Vautin, he decides to win the favor of Dolphins de Nusingen. In this he is helped in every way by dad Gorio, who hates both sons-in-law and blames them for the misfortunes of his daughters. Eugene meets Delphine and falls in love with her. She reciprocates, for he rendered her a valuable service, winning seven thousand francs: the banker's wife cannot pay off her debt - her husband, having pocketed a dowry of seven hundred thousand, left her almost penniless.

Rastignac begins to lead the life of a secular dandy, although he still has no money, and the tempter-Vautren constantly reminds him of the future millions of Victoria. However, clouds are gathering over Vautin himself: the police suspect that under this name is a fugitive convict Jacques Collen, nicknamed the Deceit-Death - to expose him, the help of one of the "parasites" of the Voke boarding house is needed. For a substantial bribe, the role of detectives is agreed to be played by Poiret and Michono: they must find out if Votren has a mark on his shoulder.

The day before the fateful end, Votren informs Rastignac that his friend Colonel Franckessini challenged Tyfer son to a duel. At the same time, the young man learns that Dad Gorio did not waste time: he rented a lovely apartment for Eugene and Dolphin and instructed the solicitor Dervil to put an end to the atrocities of Nusingen - henceforth, the daughter will have thirty-six thousand francs of annual income. This news puts an end to the vacillations of Rastignac - he wants to warn the father and son of the Typhers, but the prudent Vautren solders it with wine mixed with sleeping pills. The next morning, they do the same trick with himself: Michono mixes a potion of coffee in his coffee that causes a rush of blood to his head - he strips the insensitive Votren, and the mark appears on his shoulder after clapping with his palm.

Further events are happening rapidly, and mother Voke loses all her guests overnight. First, Tyfer comes for Quiz: the father calls the girl to him, because her brother is mortally wounded in a duel. Then the gendarmes burst into the boarding house: they were ordered to kill Votren at the slightest attempt to resist, but he demonstrates the greatest composure and calmly surrenders to the police. Imbued with an involuntary admiration for this "genius of hard labor", students having lunch at the hostel drive out the voluntary lard - Michono and Poiret. And dad Gorio shows Rastignac a new apartment, begging for one thing - to let him live a floor above, next to his beloved Dolphin. But all the old man’s dreams are crumbling. Pressed against the wall by Dervil, Baron de Nusingen confesses that his wife’s dowry was invested in financial fraud. Gorio is terrified: his daughter was in the full power of a dishonest banker. However, Anastazi’s situation is even worse: saving Maxim de Tray from a debt prison, she pawns family diamonds with Gobsec, and the Count de Resto learns about this. She needed twelve thousand more, and her father spent the last money on an apartment for Rastignac. The sisters begin to shower each other with insults, and in the midst of their quarrel, the old man falls as if mowed down - he was hit enough.

Dad Gorio dies that day when the Viscountess de Bosean gives his last ball - unable to survive the separation from the Marquis d’Ajuda, she leaves the world forever. Having said goodbye to this amazing woman, Rastignac hurries to the old man, who in vain calls his daughters to him. The unfortunate father is buried on pennies by poor students - Rastignac and Bianchon. Two empty carriages with emblems accompany the coffin with the body to the Pere Lachaise cemetery. From the top of the hill, Rastignac looks at Paris and takes an oath to succeed at all costs - and to begin with, he goes to dinner at the Dolphin de Nusingen.