The document discusses the theme of sacrifice and rebirth in A Tale of Two Cities by Charles Dickens. It argues that the theme is embodied in the characters of Dr. Manette, Charles Darnay, and Sydney Carton. Through the aid of his daughter Lucie, Dr. Manette is able to overcome his past trauma and be reborn as a new man. Similarly, Darnay and Carton transform dramatically through the story, with Carton undergoing the ultimate sacrifice that leads to his rebirth. The document asserts that sacrifice is the core theme that the skeletal structures of the characters are built upon.