We meet Mathilde (although we don't learn her name right away), an attractive, charming young girl who's born into an average family, but believes that she has the right qualities to be rich and fabulous.
Mathilde likes to spend her days hating her life and living in dreamland. She dreams of Oriental tapestries, footmen, and seducing men. If only she were rich…
Mathilde receives an invitation to a ball the Minister of Education is throwing from her husband. Just what she always wanted…but she has no dress. Fortunately, she is able to get four hundred francs from her husband. Dress? Check.
Mathilde finds something else to be upset about right before the party: no jewels. She goes to Mme. Forestier to borrow some, and after rifling through her whole collection finds the one: a diamond necklace. Jewels? Check.
Mathilde goes to the party, has the time of her life, and seriously works it. She's desired by all the men present, including her husband's boss.
Mathilde leaves the ball in a rush at 4am – she can't be seen in her raggy wrap. She and her husband wander around for a while before they finally catch a cab and go home.
Once she gets home, Mathilde has to look at herself one last time in the mirror. But when she does she finds out that the necklace is gone.
Mathilde spends the next day traumatized in a chair getting over the fact the necklace is gone, while her husband searches for the necklace all over Paris.
Mathilde goes with M. Loisel to get a new necklace. After finding a look-alike, they spend all of their money and are forced to take out loans to buy it.
Mathilde returns the replacement necklace to Mme. Forestier.
Mathilde spends the next ten years living a poor woman's life. She loses her good looks, but learns how to work.
Over ten years after the fateful party, Mathilde decides to take a stroll on the Champs Elysées, where she meets Mme. Forestier, who, unlike her, still looks young and beautiful.
Mathilde decides to tell Mme. Forestier the truth about the necklace she returned, and the last ten years of her life.
Mme. Forestier tells Mathilde that the necklace she ruined her life to replace was a fake.
We never get to see how Mathilde reacts to this crushing news.