Mathilde is born to a low-class family; with no money for a dowry, she is married to Monsieur Loisel, a clerk from the Board of Education. Mathilde–now Madame Loisel–had always felt like she should have been upper class, and is unhappy in her married life: she hates their home, their food, and her lack of fine clothing and jewelry. One evening, her husband excitedly presents her with an invitation to attend an event at the Minister of Public Instruction’s home. To the surprise of M. Loisel, Mme. Loisel throws the invitation down in dismay, weeping and complaining that she has nothing to wear to such an event. Her husband offers to give her the money for something suitable, but as the day of the ball approaches, she is still dismayed. When asked why, she replies that she is embarrassed to attend the ball without any jewels. Her husband suggests that she ask to borrow some jewels from her rich friend, Madame Forestier. She agrees and goes to see her friend the next day, greedily choosing one of Madame Forestier’s finest necklaces.
At the ball, Madame Loisel is a hit: elegant, joyful, and desired for waltzes. She and M. Loisel return home at nearly 4 o’clock in the morning, and only when they arrive home does Mme. Loisel realize she lost the necklace. After a week with no news, M. Loisel proclaims that they must replace it, and the couple finds a replacement for 36,000 francs. Loisel has 18,000 francs from his father’s will and borrows the remaining sum, bit-by-bit and making “ruinous promises”(p.36) along the way. After all this, Madame Loisel is able to return the newly bought necklace in the original’s case, apparently rousing no suspicion.
To pay off the debt, both Monsieur and Madame Loisel must work tirelessly. After ten years, they are finally able to pay off all of their debts. One day, while taking a walk, Madame Loisel runs into Madame Forestier. She approaches her old friend, but Mme. Forestier almost doesn’t recognize her. In sudden emotion, Madame Loisel reveals her entire story of losing the necklace, replacing it, and working off the cost of the replacement ever since. In response, Madame Forestier replies that the original necklace contained not actual diamonds but rather fake diamonds, meaning the original necklace cost no more than 500 francs.
Mathilde Loisel is attractive and pretty, but unhappy, very unhappy. She believes that life has played her false. She feels relegated to a lower station than she deserves. She wanted to be appreciated and loved by some rich gentleman from a good family, but instead, having no dowry, she had to settle for a junior clerk in the Ministry of Public Instruction. Her existence is one of constant frustration. She hates her plain apartment, its absence of pictures on the walls, its shoddy furniture. Even the sight of her maid, doing housework, fills her with hopeless regrets and provokes flights of fancy about more opulent surroundings. Though other women of her class may come to terms with their station in life, Mathilde never can.
She is so humiliated by her lower-middle-class existence that she even refuses to see one of her old friends whom she has known from her days at the convent school. Madame Forestier is wealthy, and Mathilde finds visits to her too painful to bear; so, she spends her days hanging around her drab flat, sometimes crying the entire time, overcome with worry, regret, desperation, and distress.
Her husband, on the other hand, seems better adjusted. He does not notice that the tablecloth has been in use for three days. When he is served a simple casserole, he can exclaim with pleasure: “Well, a good hot-pot. I don’t know anything better than that.” One day, he comes home from his office with an invitation to a party that is being given by his superior, the minister of public instruction. Instead of greeting the news with delight, Mathilde throws the invitation down on the table, saying that it is no good to her, because she has nothing suitable to wear for such an occasion. Her husband tries to convince her that it was very difficult for a junior clerk to get asked to such an event. “You will see the whole world of officialdom there,” he says, suggesting that she wear that good-looking dress she once wore to the theater. She refuses and tells him to give the invitation to a colleague whose wife is better turned out than she.
Monsieur Loisel tries another tack. He asks her how much it would cost to get a proper dress. She thinks it over, trying to estimate what an old pinchpenny like him would be willing to spend. She decides on the sum of four hundred francs that, as it happens, is exactly the amount that he has put away to buy himself a gun so he could join some friends who go Sunday lark-shooting on the Nanterre flatlands. He is not happy to forgo his pleasure but agrees.
An appropriate dress is ordered and is ready before the date of the dance. Mathilde, however, is still depressed. Now she complains that she does not have any jewelry to wear with it. Her husband suggests flowers. She is unimpressed. He then suggests that she go to her rich friend Madame Forestier and borrow some jewelry. His wife thinks it a good idea and the next day goes and explains the situation to her. Madame Forestier is more than willing to comply and goes to a wardrobe to get a large jewelry casket. She tells Mathilde to take what she likes.
Such an embarrassment of riches makes it difficult for Mathilde to make up her mind. She asks to see something else. Suddenly, she discovers a black satin case that contains a magnificent necklace, “a river of diamonds.” With tremulous voice she asks if she may borrow this item. “But yes, certainly,” says her friend. Mathilde throws her arms around her friend’s neck, and then joyously hurries home with her treasure.
At the minister’s party, Mathilde scores a success. She appears to be the prettiest woman in the room; all men’s eyes are on her. Even the minister notices her. She dances throughout the night, leaving her exhausted husband dozing in a small drawing room with three other husbands whose wives are also enjoying themselves. When the party breaks up at four o’clock, Mathilde wants to get away as fast as possible because she does not want the other women, who all wear furs, to notice her plain cloth coat. She runs out to the street hoping to find a cab, but the search takes her down to the Seine where, at last, she and her husband find an old dilapidated brougham stationed along the embankment. The ride back to their dismal apartment is sad for Mathilde with her fresh memories of her triumph.
Once home, as she is taking off her wraps, she discovers that the necklace is no longer around her neck. They search her clothes: nothing. Her husband goes out and retraces their path home. He returns several hours later having found nothing. The next day, he goes to the police and files a report. He then advertises in the lost-and-found in the papers, but still, nothing. To give them time to continue the search, they tell Madame Forestier that the clasp on the necklace is being repaired. After five days, however, when nothing shows up, they decide that the necklace is truly gone and they must have it replaced.
They take the necklace case from jeweler to jeweler to find a strand of diamonds that matches the one lost. They finally see one in a shop at the Palais-Royal. The price, with a four-thousand-franc discount, is thirty-six thousand francs. The Loisels pay for it with an eighteen-thousand-franc inheritance that the husband has received from his father, and by borrowing the rest in small amounts, thereby mortgaging their lives for the next decade. The replacement necklace is returned to Madame Forestier, who remarks rather coldly that it should have been returned sooner because she might have needed it. She does not bother to open the case.
The Loisels are left with their debts. They get rid of their maid. They move to a poorer apartment. The wife now has to do all the menial work herself: wash the sheets, carry garbage down to the street, carry up the water, do her own shopping, bargaining with everybody to save a few sous. The husband moonlights, working in the evenings for a bookkeeper and often at nights, doing copying at twenty-five centimes a page. This goes on year after year until the debt is paid. The time of penury has transformed Mathilde into a poor, prematurely old hag, with a loud voice, red hands, and neglected hair, but in her misery she often remembers the minister’s ball, where she had her great success. What, she asks herself, would have been her fortune had she not lost the necklace?
One Sunday, as she strolls along the Champs-Elysees, she sees Madame Forestier taking a child for a walk. Jeanne Forestier is still young-looking and attractive. Now that the debt for the necklace has been satisfied, Mathilde Loisel decides to tell her old friend everything that happened. She stops to speak to her but is not recognized until she introduces herself. She explains that life has been pretty grim. She tells her about the lost necklace, how she had it replaced and for the past ten years has been slaving to pay for it. She is relieved that the long ordeal is over, and naïvely proud that her friend never knew that a different necklace had been returned to her.
Madame Forestier is deeply touched. Taking both of her friend’s hands she says, “Oh! My poor Mathilde! But mine was a fake. It was worth no more than five hundred francs!”