After Jacob Marley comes to warn Scrooge about the three ghosts that will visit him the ghost of Christmas Past arrives. She takes scrooge into his past Christmas's and it brings back memories Scrooge tried so hard to forget.
After Christmas Past returned Scrooge to his Bed then arrived the Ghost of Christmas Present. The Ghost took him to Bob Cratchit's house which was small and had many people living in it. The Ghost then took him to his nephew's house were they were poor but they were happy.
Christmas Present Disappears and then moments later comes a black figure. This must've been the Ghost of Christmas Future. The Ghost took him to the Future. They overheard a conversation of 3 business men talking abut who scrooge thought was Jacob Marley. They then went to a shop were they were selling Scrooge's belongings. He found out that he was the one dead in the Future. And with him Tiny Tim had died to. Scrooge begged the spirit to forgive him then he was back in his bed.
Scrooge wakes up and he is in his bed. He is happy to be back in his house. He keeps his promise to the spirit and changes. First he pays a boy to go buy the biggest turkey and bring it back to him. He delivers this turkey to Bob Cratchit's house anonymously. Then he goes to his nephew Fred's house to join him for Christmas.
The next day Bob Cratchit comes to work and Mr. Scrooge surprises him with a huge pay raise. This allows Tiny Tim (Bob Cratchit's son) to get healthier and live a full life. Scrooge was like Tiny Tim's second dad.
Scrooge had never had the best past Christmas's which is probably why he was so grumpy and greedy. But scrooge learned treat others the way you want to be treated. When he encountered the Future Ghost he saw that people didn't respect him when he has passed away. So he changed.