This great short story by Guy de Maupassant is well worth reading for yourself as it contains a moment of almost perfect situational irony. However, I will outline the main events for you and hopefully this will interest you in the story as a whole.
As the story opens, we are introduced to Mathilde Loisel, who is a character who appears doomed to live a live where she feels constantly dissatisfied. Although she is middle-class, she constantly yearns and daydreams for a better quality of life, spending more of her time daydreaming than anything else. Finally, when she and her husband are invited to a ball, she feels she has her chance. She goes to an old friend who has had much more success in life and borrows a diamond necklace from her. With this necklace, the ball passes wonderfully, and all her dreams are fulfilled. However, the next day, she realises she has lost the necklace. Filled with shame, Mathilde and her husband commit themselves to a life of poverty in order to repay the loan they have to take out to buy a new necklace so her friend doesn't realise it was lost. finally, years later, after Mathilde has been completely transformed by a life of drudgery, she stumbles across her old friend and tells her about the necklace, only to receive the news that the necklace was actually a fake.