Madame Loisel desperatly wants a better social life, her husband gets her an invitation for a party.
Madame Loisels husband goes out and buys her a dress and shoes and stuff to go to the party. She didn't get a necklace so she asked her friend to borrow a necklace for the party.
Madame Loisel loses the necklace on the cab when she is on her way home. She gets upset and worried.
Her husband says that they will use his fathers enharitance and take out a loan to replace the necklace.
Madame Loisel and her husband give her friend the new necklace and end up moving out of her house because she can't afford to pay for her fancy house anymore. There life changes.
Madame Loisel sees her friend somewhere one day and she doesn't even recognize Madame Loisel because she is so different. Madame Loisel ends up telling her the truth and her friend tells Madame Loisel that it was fake anyway and now she has a real one.