A Tale of Two Cities Lesson Plan

What is the importance of Sydney Carton's willingness to step in for Charles Darnay at his trial, ensuring his acquittal on charges of espionage and treason?

As a reminder, Charles Darnay's first trial is thrown into disarray when Mr. Carton--a man who looks almost identical to Darnay--reveals himself. In fact, while there is other evidence presented in Darnay's defense, Carton's appearance is the primary reason that Darnay is acquitted of the charges against him. This scene is yet another early instance of the theme of Doubles & Duality, which arises throughout the novel. Indeed, Dickens introduces the theme of Doubles & Duality beginning with the very title...