Denise and her brothers, Pépé and Jean, arrive in Paris. Their father and mother have recently died, and they are going to stay with their uncle Baudu, who owns a drapery shop called the Vieil Elbeuf. As they walk to his shop, they pass the Ladies’ Paradise—a huge, enchanting department store. Denise and her brothers discover that the Baudus are sinking towards bankruptcy. Their customers have been driven away by the Ladies’ Paradise—a store that has multiple departments, a captivating atmosphere, and cheap prices. Baudu has no job for Denise, so she decides to apply at the Ladies’ Paradise—a decision that offends the Baudus, who hate modern business.
The story leaves Denise to follow Octave Mouret—the owner of the Ladies’ Paradise—arriving in his office after a night of partying. He looks in gratitude at the portrait of his late wife, Madame Hédouin, and then goes on his daily inspection of his store, the great “machine.” Mouret decides to sell a fancy silk at a loss to himself to ensure customer trust. He founds his store on the principle of exploiting the universal desires of all women. This has proved wildly successful, even though Bourdoncle warns him that women will “have their revenge” one day. Mouret comes upon Denise, who is at that moment applying to work in the ladieswear department. Madame Aurélie—the buyer of the department—thinks that Denise is too shy and skinny, but Mouret takes a liking to her and has Madame Aurélie hire her. Denise, who had seen Mouret earlier on the street, feels the same inexplicable fear around him that she had felt earlier.
That weekend at Madame Desforges’s house, a group of aristocratic ladies—Madame de Boves, Madame Guibal, and Madame Marty—gather for tea. They are joined by Vallagnosc, Mouret, and Baron Hartmann. Mouret persuades Baron to sell him property adjacent to the Ladies’ Paradise for an expansion plan. He talks up the Ladies’ Paradise, and the ladies get excited. The following Monday, the ladies attend a sale at the Ladies’ Paradise—an event that seduces rich and poor women alike with grandiose displays and emotional tricks—and become entranced by it in their own ways.
Meanwhile, the salesgirls bully Denise out of sales, and she struggles to pay Pépé’s room and board and the money to cover Jean’s constant affairs. Pauline—her one friend at the Ladies Paradise—suggests that Denise make extra money by taking a lover, but Denise is naturally disinclined to a sexual lifestyle. She goes on a day trip to the country with Pauline and her boyfriend, where she is distraught to see Hutin—a salesman at the Ladies’ Paradise whom she has a crush on—acting obscene in a bar. She also runs into Deloche—a salesman at the Ladies’ Paradise. He confesses his love for Denise, but she thinks of him only as a friend. The slow season at the Paradise starts, and all the salespeople live in fear of being fired. One day, Jouve—who has a vendetta against Denise because she physically rejected his predatory advances—catches Denise in the basement talking to Jean, and, believing Jean to be Denise’s lover, has Denise fired immediately. He doesn’t consult Mouret, who has since developed feelings for Denise.
Denise then lives through a period of intense poverty. She and Pépé rent a dingy room above a small umbrella shop owned by Bourras. Denise refuses to make money as a prostitute like the other poor women around her, and instead makes a little money working for Bourras, who rants constantly about the obscenity of the Ladies’ Paradise. Finally, Denise gets a job working for Robineau—the buyer of the silk department who was also recently fired—in his new drapery shop. Denise likes the Robineaus, but when she runs into Mouret in a park, they have an impassioned discussion in which she shares her preference for modern business. Robineau and the Baudus (whom Denise has reconciled with) refuse to join what she calls “the natural development of business.” Denise is distraught that the small businessowners are letting themselves be ruined, and that her cousin Geneviève—whose fiancé Colomban is in love with Paradise salesgirl Clara—is dying of heartbreak.
Denise accepts an invitation from Mouret to return to the Ladies’ Paradise. There is another big sale, and Mouret intentionally disorganizes the store so as to make his female customers get lost and thus spend more. Madame Marty goes into a fever of spending while Madame de Boves feels tempted to shoplift. After the sale, Mouret promotes Denise to assistant buyer of the ladieswear department. Soon after this, Denise gets a letter from Mouret asking her to dine with him—something he has asked of many salesgirls, including Clara, who afterwards become his mistresses. Although Denise has since realized she loves Mouret, she doesn’t want to be his mistress. While the news of the letter circulates through the staff, Mouret finds Denise counting stock in the pattern room. He begs her to accept him and confesses he loves her, but she rejects him.
Soon after, Madame Desforges—who could tell at the sale that Mouret loves Denise—jealously invites Mouret to a tea party and sends for Denise at the same time to fit a coat for her. Madame Desforges bosses Denise around and humiliates her by flaunting her relationship with Mouret. Finally, Denise breaks her calm, insinuating that Madame Desforges is overweight. Mouret defends Denise and breaks his ties with Madame Desforges. At the same tea party, Mouret persuades Baron to support his expanding the Ladies’ Paradise onto an entire street—the Rue du Dix-Decembre. He also fires Bouthemont—who has since befriended Madame Desforges—and Madame Desforges takes him under her wing to finance his own department store.
Construction starts on expanding the Ladies Paradise onto the Rue du Dix-Decembre. Despite his dreams being realized, Mouret feels that his power and money are meaningless since he can’t have Denise. Bourdoncle—who is worried that Denise is “the revenge” he has been warning Mouret about—tells Mouret that Denise has been having relations with Deloche. Furious with jealousy, Mouret again confesses his love to Denise. She rejects him again but assures him that she has no lovers. After this, Denise becomes buyer of a new department for children and uses her position to make changes to the Ladies’ Paradise: she opens a school for employees and a maternity ward for the pregnant salesgirls like Pauline, who has since married Baugé.
When Colomban runs off with Clara, Geneviève becomes seriously ill and soon passes away. The small tradespeople—all dismal in their bankrupt state—gather for her funeral. Shortly after, Madame Baudu passes away. Robineau goes bankrupt, fails an attempt at suicide, and then retires to the country with his wife. Bourras goes bankrupt and Mouret demolishes his shop, expanding the Ladies’ Paradise into its space. Baudu and Bourras both refuse Denise’s offers of help. Denise is distraught by the suffering of the small businessowners but sees their demise as necessary for the progress of modern business.
The new Rue du Dix-Decembre opens and is inaugurated by a “white sale” in which the store is decorated like a wedding. Tired of all the rumors circulating about her and Mouret, Denise plans to leave the Ladies’ Paradise after this sale. Jean (who is now married) and Pépé (who goes to school in Paris) visit Denise in the children’s department. Mouret, making his usual inspection, is touched by Denise’s love for her brothers, and asks Denise to come to his office after the sale. Meanwhile, Madame Desforges, Madame de Boves, and Madame Marty (whose husband went crazy after she spent all his money) shop in all the departments. Jouve catches Madame de Boves stealing some lace, and she is taken to Bourdoncle’s office and searched. Mouret observes all these women who are at his mercy and feels suddenly that he wants to surrender to Denise. After the sale, the money bags are brought to Mouret’s desk, but he is indifferent to the new record of one million dollars that they contain. Denise comes to his office, and Mouret proposes to her. Denise accepts, and they fall into each other’s arms while Madame Hédouin seems to smile in her portrait above them.
