Taken from a short story by Maupassant, the action revolves around a middle-class couple. The husband borrows a pearl necklace from a jeweller friend for his wife to wear to a party. It is much admired at the party, but she is followed home by a burglar who breaks in and steals it. The next morning, the friend needs it back. It belongs to a customer he had been repairing it for. Excuses are made and they promise to return it later. They try to borrow money from friends to buy another, but without much success. Eventually, driven to desperation, the husband steals money from where he works and buys a replacement, which is returned to the owner. The husband, however, was seen taking the money from the safe at work, and is duly fired. The couple descend into poverty, and the wife reproaches herself for her vanity which has led them into such straits. The husband finds work and things improve. His supervisor, incidentally, is the husband of the lady who gave the party where the whole story began. This supervisor is, however, being blackmailed, and when the husband finds out, he follows the supervisor and saves him during a physical attack by the blackmailer. While the supervisor is in hospital, he is visited by his saviour and his wife, and their wives, old friends, meet. The husband describes their situation and how it began with the loss of the pearl necklace. The supervisor is guilt-stricken. It turns out that he had noticed how impressed his wife (at the time he was one of her suitors) was impressed at ‘that’ party by the pearl necklace. He had paid a ruffian to steal it and bring it to him, so he could present it to her and win her heart. This it did, since they are now married, though he has regrettably ruined the other couple’s lives in the process. He now offers help, and though his agency, the husband takes over the supervisor’s job at the factory, and by selling the necklace, is able to purchase back his original house. All is back as it should be, though the wife has vowed to never let her vanity lead her astray again.