Eudora Welty, noted American Southern Local Color short story writer and novelist, once said that if a writer were to change the setting of a story, then the writer would have entirely changed the story: the setting is the story.
Every story would be another story, and unrecognizable if it took up its characters and plot and happened somewhere else .... Fiction depends for its life on place. Place is the crossroads of circumstance, the proving ground of What happened [where]? Who's here? Who's coming [to where]? (Eudora Welty qtd by Carol A. Bailey in A Guide to Qualitative Field Research)
Another way to say to this is to say that setting is the situation surrounding the characters, the situation in which and to which the characters act and react. A contemporary definition for setting goes beyond geographical location plus temporal location (place and time, presently and historically) to call setting the milieu of the story; milieu includes social, cultural, ethnic and economic context as well as geographical and temporal location.
The dynamic affect upon characters of this all-inclusive-situation view of setting can clearly be seen in A Tale of Two Cities. If the characters were removed from the historical, sociocultural, economic and geographical time of the French Revolution, none of what happens to them, because of them or because of their actions or reactions would have happened. In any other all-inclusive-situation setting, Darnay would not have been an expatriate exile with a disguised name. Doctor Manette would not have been imprisoned and suffering the loss of his sanity. Lucie and Mr. Lorry would not have gone to fetch him home after his release into 20-year deferred freedom. Darnay would not have been imprisoned in France and saved by Sydney Carton's substitution of himself for the more fortunate Darnay.
In order to prove the hypothesis that the all-inclusive-situation setting is a controlling factor of character circumstances, discuss relevant characters from within their situations as those relate to the French Revolution. For example, to prove this hypothesis, examine and explicate how and why it is that Charles Darnay came to be an exile in England. Include in your discussion Book the Second, Chapter IX, in which Darnay returns to France to confront his uncle the Marquis. Two other clear examples to examine and explicate are the circumstances of Doctor Manette and Sydney Carlton. The deep and heroic tragedies faced by both men will strongly make a case for the hypothesis as will Darnay's escape from murder charges in England.
From the dimly-lighted passages of the court, the last sediment of the human stew that had been boiling there all day, was straining off, when Doctor Manette, Lucie Manette, his daughter, Mr. Lorry, the solicitor for the defence, and its counsel, Mr. Stryver, stood gathered round Mr. Charles Darnay—just released—congratulating him on his escape from death. (Book the Second, IV. Congratulatory)