Madam Loisel thinks that she deserves a better life , and she complains to her husband Monsieur Loisel that she desperately needs a better social life. However in this time social classes were defined by the amount of money you had. Madam and Monsieur Loisel were middle class. However her husband had gotten her a invitation to a very fancy/wealthy party
Once she has gotten the invitation to the party she starts to freak out saying she cannot possibly go without expensive things. So Monsieur Loisel gives her his 400 francs for a dress that he was going to save for a rifle.
She goes over to her friends Madam Frostiers house , and asked her for some jewelry , and she fell in love with a diamond necklace.
In the climax Monsieur and Madam Loisel Get home , and realize that the diamond necklace she had borrowed from a friend is now gone , and missing.
The Falling Action to this story is that once the Loisels realize that the necklace is gone they did not want to tell their friend that the necklace was lost. So they had to improvise. Monsieur Loisel took the rest of the inheritance that he had left , and had to go to loan sharks to buy the 45,000 franc necklace. So they replaced the necklace , and things went good.
Many years later Madam Loisel had seen her friend , and had confessed the truth of what had really happened. However her friend had confessed that the necklace she gave her was a fake only worth 500 Francs.