Most of the characters in Atonement feel a need to atone for their mistakes. However, not all of these mistakes are of the same magnitude. Robbie and Cecilia feel the need to atone for their mistake of failed communication. After years of unresolved romantic feelings for one another, their relationship explodes in dramatic fashion. Robbie and Cecilia realize that they have made a mistake by not acknowledging their love sooner, so the intensity of their love is an act of atonement: They are making up for lost time by loving each other even more intensely.

After making her false accusation, Briony’s entire life becomes a quest for atonement. She grows up, matures, and realizes that what she did to Robbie and her sister was wrong. The young aspiring writer believed that she thoroughly understood the world around her but, as she grows, she realizes the depth of her mistake. When the horror of the situation dawns on her, she begins to deny herself pleasures as a form of self-chastening. She changes the course that she had always planned for herself when she turns down the opportunity to attend Cambridge University, a decision which hampers her ambition to become a writer in the future.