Atonement Summary

On a warm day in 1935, young Briony Tallis is disappointed by the performance of her play by her cousins, pushing her to abandon playwriting and move towards adulthood. Her sister, Cecilia, returns home from her graduation, experiencing a strained interaction with Robbie, their charlady's son, leading Briony to misunderstand the situation. As Robbie realizes his feelings for Cecilia, he accidentally entrusts Briony with an inappropriate letter for Cecilia, which she reads and misunderstands further. When Cecilia and Robbie admit their feelings for each other, Briony walks in on them, misinterpreting their passion as violence.

During dinner, when the twin cousins disappear, Briony stumbles upon Lola, one of the cousins, being assaulted. She impulsively accuses Robbie, leading to his arrest. After serving three years in jail, Robbie enlists in the army in exchange for his early release. He and Cecilia maintain their relationship through letters, with Cecilia cutting off her family for their part in his wrongful conviction. Robbie clings to a hopeful future while facing the horrors of war. Meanwhile, Briony trains to become a nurse, grappling with guilt over her false accusation.

Years later, Briony, now a nurse, is overwhelmed with guilt over the injustice she perpetrated. She's further shamed when she realizes that Paul Marshall, now married to Lola, was the real perpetrator of the assault. Briony attempts to right her wrong by promising to revise her testimony, but unfortunate circumstances prevent her from doing so. As an old woman, Briony is faced with the realization that her attempts at atonement have been in vain. She writes a novel in an attempt to provide the happy ending that Cecilia and Robbie were denied in real life, knowing it can only be published posthumously. In her final moments, she imagines a joyous gathering, with Cecilia and Robbie present, signifying her yearning for the peace she deprived them of.