Briony Tallis writes a play called The Trials of Arabella to perform for her brother Leon's homecoming.

Cecilia and Robbie argue at the garden fountain; the vase breaks and Cecilia strips to dive in and retrieve the pieces.

Robbie asks Briony to deliver his letter to Cecilia, not realizing he has handed her the wrong, obscene draft.

Robbie and Cecilia meet in the library, confess their long-suppressed feelings, and have sex for the first time.

Briony walks in on Robbie and Cecilia in the library and believes she is witnessing Robbie attacking her sister.

The twins leave a note saying they have run away, and the family splits into search parties across the estate.

Briony finds Lola being sexually assaulted in the dark and convinces herself that Robbie is the attacker.

Briony tells the police she witnessed Robbie rape Lola, and her testimony leads directly to his arrest.

Police handcuff Robbie and lead him away as Cecilia weeps and his mother shouts that he is innocent.

Robbie is released from prison early on the condition that he enlists in the British Army.

Robbie and Cecilia meet in London for thirty minutes before he ships to France; they kiss and he promises to return.

Robbie, wounded by shrapnel, marches through war-torn France toward Dunkirk with Corporals Mace and Nettle.

Briony turns down her place at Cambridge University and moves to London to train as a wartime nurse.

Briony attends the wedding of Lola and Paul Marshall but says nothing when invited to object to the union.

Elderly Briony reveals her novel's happy ending was invented; Robbie died at Dunkirk and Cecilia was killed in the Blitz.

Atonement opens with thirteen-year-old Briony writing a play for her brother's return and watching her older sister Cecilia in a confusing encounter with Robbie Turner at the garden fountain. After misreading a passionate library scene and failing to clearly identify an attacker in the dark, Briony falsely accuses Robbie of rape, sending him to prison. Released only by agreeing to enlist in the army, Robbie manages one brief reunion with Cecilia in London before shipping to France. Briony, haunted by her mistake, becomes a wartime nurse and attends Lola's wedding to the real rapist, Paul Marshall, but cannot bring herself to speak. In the novel's devastating epilogue, elderly Briony reveals that her hopeful version of events was a fiction she invented, and that Robbie died at Dunkirk while Cecilia was killed in the London Blitz.

The headline events that define Briony's lie and its consequences.

Briony tries to rehearse her play with her cousins but grows frustrated when they cannot learn their lines.

Paul Marshall arrives at the Tallis estate with Leon and gives the twins chocolate from his family's factory.

Emily lies in bed with a migraine, listening to family movements through the house and worrying about each of her children.

Robbie takes a bath after the fountain incident and realizes for the first time that he has deep feelings for Cecilia.

Cecilia reads Robbie's misdirected letter and, despite its crude language, realizes she has always been in love with him.

Briony shows Lola the obscene contents of Robbie's letter, and Lola agrees that Robbie seems dangerous.

The family sits down to dinner, and Briony notices that Paul Marshall has a fresh two-inch scratch on his face.

When Cecilia finally speaks to police, her insistence that her encounter with Robbie was consensual is dismissed entirely.

Cecilia leaves the Tallis estate and cuts off all contact with her family over their accusation against Robbie.

Robbie and Cecilia exchange letters while he is in prison, hiding their true feelings in oblique literary references.

A German bomber attacks the soldiers' convoy on the road to Dunkirk, killing a major and many others.

Scores of ambulances arrive at Briony's London hospital carrying wounded soldiers from France, overwhelming the nursing staff.

Briony bandages the destroyed face of a soldier whose wounds have left him entirely unrecognizable.

Briony submits an autobiographical story called Two Figures by a Fountain to a literary magazine.

Elderly Briony's family gathers at the Tallis estate, now converted into a hotel, to celebrate her seventy-seventh birthday.

Before the central crisis unfolds, the Tallis household simmers with unspoken frustrations: Briony's play rehearsals collapse, Paul Marshall makes a suspicious impression on young Lola, and Emily lies in bed listening to a family she cannot properly tend to. Robbie's private realization of his feelings for Cecilia and her reciprocal discovery upon reading his letter reveal how close they came to happiness before events overtook them. The family dinner, marked by Paul's unexplained scratch, sets the stage for disaster, and in the aftermath Cecilia's dismissed testimony and permanent estrangement from her family show how completely Briony's lie destroyed their world. Robbie's prison letters to Cecilia and her loyalty to him are the one thread of hope he carries into war. Years later, Briony endures the horrors of wartime nursing and submits her autobiographical fountain story, while elderly Briony's birthday celebration at the converted Tallis estate marks the bittersweet end of a life shaped by a single terrible lie.

The supporting moments and relationships that shape the novel's tragedy.

Briony reluctantly surrenders the lead role in her play to Lola, resenting the attention her older cousin will receive.

Briony watches from a window as Cecilia strips and dives into the fountain, misreading the strange power Robbie seems to hold over her sister.

Leon invites Robbie to dinner at the Tallis house despite Cecilia's attempts to make him take back the invitation.

Robbie writes a vulgar letter for release, then composes a sincere letter expressing his true feelings for Cecilia.

Robbie realizes he has given Briony the wrong envelope but cannot reach her before she enters the house.

Briony reads Robbie's obscene letter and decides he is dangerous, convincing herself she must protect her sister.

Lola is brought into the Tallis house after the assault, dazed and unable or unwilling to identify her attacker.

Briony takes the obscene letter from Cecilia's room and shows it to the police and to Leon.

Robbie falls into a feverish sleep in a ruined house at Dunkirk, asking Nettle to wake him when the evacuation boats arrive.

Briony learns that Paul Marshall has proposed to Lola and feels deeply implicated in a union born of trauma.

Briony receives a rejection from the literary magazine, which criticizes the limited perspective in her fountain story.

Dying French soldier Luc Cornet mistakes Briony for his girlfriend and asks if she loves him; she says yes.

Robbie arrives at Cecilia's apartment while on leave and, seeing Briony, launches into a rage of long-suppressed fury.

Briony tells Cecilia and Robbie that Paul Marshall, not Danny Hardman, was the man who raped Lola.

A doctor tells elderly Briony she has vascular dementia and will soon begin losing her memories.

The novel's tragedy is built from a series of small but irreversible turning points, beginning with Briony's wounded pride over her play and her failure to understand what she observes at the fountain. Robbie's fateful double letter sets a chain of misreading in motion, and Briony's certainty that he is dangerous hardens into a false accusation after she finds Lola in the dark, while stolen evidence helps condemn him. In France, Robbie's feverish collapse at Dunkirk signals an end he will never escape, while back in England Briony slowly pieces together the truth about Paul Marshall far too late to save anyone. Her final confrontation with Robbie and Cecilia and her revelation about the real rapist exist only in the novel she invented as atonement. That act of invention is itself shadowed by a dementia diagnosis, which threatens to claim the very memories she has spent a lifetime trying to make right.