Christmas Carol----Chain?

The iron chains represent that the prisoners should be released from the prison.
It represents the workmen from the workhouse should be released from bonding by Scrooge.
The prisons,the workhouses, the three ghosts are a chain of events (a human chain) in the progressive sequence,series,chapters of the Book.

The story related to Christmas in that the chief character----Scrooge who should learnt how to be a kind person,a kind action, a kind remark given to the public in a charitable,philanthropic way in this well-meaning,warm-hearted Christmas Seasons.If he be sympathetic,he'll get a thoughtful reward.
"A Christmas Carol" is a novel by Charles Dicken.