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.