Ebeneezer Scrooge was visited by Jacob Marley and he was warned about the 3 spirits.
The clock strikes one and Scrooge was approached by the Ghost of Christmas Past and they went out to the past and Scrooge observed his past once again.
Scrooge was approached by the Ghost of Christmas Present and is observing whats going on in Bob Cratchits house.
The last of the 3 spirits The ghost of Christmas yet to come takes him to the future to show him that he'll die with Jacob Marley's fate if he doesn't change.
Scrooge wants to change to not die with Marley's fate. He buys the biggest turkey for the Chratchits and gives Bob a raise. He gives the poor money then for the rest oh his life he keeps the spirit of Christmas alive in his heart as well as anyone.
The theme of Christmas Carol by Charles Dickens is...Its never to late to change and as long as you changes that's all that matters.