Scrooge lives an angry and miserly existence, hoarding his money and rejecting the positive emotions of the Christmas season. He's a big ol' bummer.
Scrooge's bitterness isolates him from anyone he ever comes across. On Christmas Eve, we see him get into a fight with his nephew Fred who just wants to invite him over for dinner, accuse his clerk Cratchit of theft because Christmas is a paid vacation day, and yell at a neighbor collecting money for the poor. Nice attitude, buddy.
Since none of the living can get through to him, the dead take over, and Scrooge gets a visit from the ghost of his partner Marley, who tells him to shape up or ship out.
One by one, the ghosts of Christmas Past, Present, and Yet to Come show up to remind Scrooge that he was once a normal person, that his wealth could do a world of good to those suffering right near him—like the youngest son of the Cratchit family—and that if he doesn't mend his ways he's going to end up dead and totally unmourned.
Is Scrooge doomed to a life of being hated by everyone and then to a death without anyone shedding a tear or can he get his life in order in time? Are Tiny Tim and the rest of the Cratchit family doomed to poverty, illness, hunger, and death? Is it all fate, or does he have any power here? Seriously. We're asking.
After the ghosts leave, Scrooge takes some steps in the right direction. He gives Cratchit a raise and sends him and his family a giant turkey for Christmas dinner, he gives a bunch of money to the charity collector, and he shows up at Fred's party after all. Scrooge no more.
Scrooge continues his self-reformation and becomes a completely upstanding, excellent, generous, and friendly fellow all around. Everyone who knows him says that he is the very definition of the Christmas spirit. Well that was fast.