Mathilde Loisel, a beautiful woman who was not born into a rich family, marries a man of the same status.
She gets invited to a very extravagant ball, but has nothing to wear. She then asks her husband for 400 francs to buy a gown.
She borrows an "expensive" necklace from her friend. SH has an amazing time at the ball dressed in a gown and confidence.
She loses the necklace while at the ball and can't find it anywhere. She and her husband take out many loans to pay for a really expensive diamond necklace to replace it.
She and her husband work to pay off the replacement necklace for 10 years.
She runs into her friend while in town after 10 years. When she finally tells her friend the truth about the necklace, she discovers the necklace she originally borrowed was fake, and only cost her 500 francs.