From Wikipedia:

Written is 1843 by Charles Dickens, the tale begins on a "cold, bleak, biting" Christmas Eve in 1843 exactly seven years after the death of Ebenezer Scrooge's business partner, Jacob Marley. Scrooge has no place in his life for kindness, compassion, charity or benevolence. He hates Christmas, calling it "humbug", refuses his nephew Fred's dinner invitation, and rudely turns away two gentlemen who seek a donation from him to provide a Christmas dinner for the Poor. His only "Christmas gift" is allowing his overworked, underpaid clerk Bob Cratchit Christmas Day off with pay - which he does only to keep with social custom, Scrooge considering it "a poor excuse for picking a man’s pocket every twenty-fifth of December!".

Returning home that evening, Scrooge is visited by Marley's ghost. Marley warns Scrooge to change his ways lest he undergo the same miserable afterlife as himself. Scrooge is then visited by three additional ghosts – each in its turn, who accompany him to various scenes with the hope of achieving his transformation.

The first of the spirits, the Ghost of Christmas Past, takes Scrooge to Christmas scenes of his boyhood and youth, which stir the old miser's gentle and tender side by reminding him of a time when he was more innocent. They also show what made Scrooge the miser that he is, and why he dislikes Christmas.

The second spirit, the Ghost of Christmas Present, takes Scrooge to several differing scenes - a joy-filled market of people buying the makings of Christmas dinner, the celebration of Christmas in a miner's cottage, and a lighthouse. A major part of this stave is taken up with the family feast of Scrooge's impoverished clerk Bob Cratchit, introducing his youngest son, Tiny Tim, who is seriously ill but cannot receive treatment due to Scrooge's unwillingness to pay Cratchit a decent wage.

The third spirit, the Ghost of Christmas Yet to Come, harrows Scrooge with dire visions of the future if he does not learn and act upon what he has witnessed including Tiny Tim's death. It is shown that Scrooge has passed away where businessmen planned to attend if lunch is provided. Scrooge's charwoman Mrs. Dilber had stolen some of Scrooge's belongings and given them to a fence named Old Joe. Scrooge's own neglected and untended grave is then revealed, prompting the miser to aver that he will change his ways in hopes of changing these "shadows of what may be."

Scrooge awakens on Christmas morning with joy and love in his heart, then spends the day with his nephew's family after anonymously sending a prize turkey to the Cratchit home for Christmas dinner. Scrooge has become a different man overnight and now treats his fellow men with kindness, generosity and compassion, gaining a reputation as a man who embodies the spirit of Christmas. The story closes with the narrator confirming the validity, completeness and permanence of Scrooge's transformation.