We pick up Briony in 1999 on her 77th Birthday as she is about to make her “last visit” to the Imperial War Museum library in Lambeth. We learn Briony has received “dozens of letters” from Colonel Nettle to help her tell her story, of which he will donate to the library.
Briony informs the reader of a recent diagnosis of vascular dementia. In short, she is losing her mind (similar to Alzheimer) and acknowledges that soon she will not recognize, nor remember any parts of her life. She is strangely comfortable with this news. As her driver takes her from her apartment to the library, Briony runs through a shopping list of what most of the characters in her life have done and gone on to become. Notably, Leon was married four times and is still alive, “heroically nursing his wife” and raising boisterous children alone, and Lord and Lady (Paul and Lola) Marshall have been extremely financially successful and well respected British citizens. In fact, when Briony gets to the museum, she is surprised to see Lord and Lady Marshall coming down the large steps towards their car. They are concealed and protected by servicemen, and Briony avoids seeing them and being seen. She comments on how old Paul has become and how vibrant Lola still is, despite her age of 80 years. Briony confesses to the reader that Lola will “certainly outlive me” (338).
Following her visit to the museum and thanking all the workers their for her help, she returns to her flat. It is there that we learn she was married to a man named Thierry, who died fifteen years prior. Briony then gets in another car with a young Ph.D. student driver and heads to Tilney Hotel (342) for the first time since Emily’s funeral. The Tallis household and park had been turned into a golf course and hotel. The lake is gone. Briony’s suitcase is taken to Auntie Venus’s room as she explores the main floor of the now hotel, stopping outside the door to her old room. Pierrot’s grandson Charles is the one who has organized the event.
A little later, Briony enters the old library that is now a reception room to the applause of over 50 relatives, whom most she does not recognize. Leon is there and mostly incoherent in a wheelchair. Pierrot is there also, but we learn Jackson died fifteen years ago. It is revealed that Briony is a well-accomplished writer and that her books are being studied in high schools across England (345). She is then seated for a special performance, and she is unaware of what it will be.
A group of the younger relatives (mostly Quinceys) appear on a mock-stage and begin a performance of "The Tales of Arabella." Briony is shocked, pleased, and in a state of bewilderment, wondering where, whomever it was, found a copy of her very first play. She looks at Pierrot who is crying in happiness and can only assume he has something to do with it. When the play ends, the crowd “rises in uproar.” Briony is the only one who notices Pierrot, seated in the corner, “completely overcome” (348). Briony ponders what is on his mind and whether he is completely reliving that summer when he was just a child and his parents left him for their own selfish reasons. Briony apologizes to Pierrot and takes blame for not letting the play happen back in 1935.
The party ends and we jump forward to Briony sitting at her writing desk at five in the morning. She explains how her last novel should have been her first, the one that has gone through many versions from January 1940 to March 1999. Her complete intention after the second draft was to “set out to describe” the only one real crime of wartime Britain – Lola’s, Marshall’s, her own. Briony informs the reader of her intention to wait until all the characters are dead before publication so she can avoid the risk of being sued for libel for not changing names, something she refuses to do as part of her “atonement.”
In her final address to the reader, Briony lets go of the last twist of her tale. She explains, “it is only in this last version that my lovers end well, standing side by side on a South London pavement as I walk away” (350). The long paragraph describes how the part of her book where she is in London in 1940, and meets Robbie and Cecilia in their flat, was completely made up. The narrator explains how Robbie never made it off the beach in Dunkirk and that Cecilia died shortly thereafter in a London bombing. Briony explains how after the wedding, the real story is that she was too cowardly to confront a bereaved sister, which led to never seeing her again before her death shortly thereafter. The letters between Robbie and Cecilia, the "two lovers," are now in the archives of the war museum and not her possession. Her explanation is that she did not think the reader would want to believe that they never met again, lived together again, and loved again. Briony finally explains that as long as her book is read, her version will be the one that will “survive to love” (350) rather than the sadness of “what really happened.”
Briony makes a final plea to the reader: “How can a novelist achieve atonement when, with her absolute power of deciding outcomes, she is also God? There is no one, no entity or higher form that she can appeal to, or be reconciled with, or that can forgive her. There is nothing outside her. In her imagination she has set the limits and the terms. No atonement for God, or novelists, even if they are atheists. It was always an impossible task, and that was precisely the point. The attempt was all” (350-51). Briony's final act of atonement was to fictionally give her lovers happiness but never let them forgive her. She then debates if she should have gone further and brought Robbie and Cecilia, alive, happy and old in one another’s arms, to her 77th Birthday party, and states, “It’s not impossible.”
Finally, Briony clearly establishes herself as the author. This creates a massive shift in form--it went from a third person narrative to a first person voice in a Chinese-box (story within a story) styled text. Briony's "atonement" is achieved through the same agent her crime was caused in the first place: imagination, creativity, writing. On the one hand, the book exposes her crime, on the other, it uses 'make-believe' to atone her guilt. This admission puts into question how historically accurate any of this is.
The artificial ending reverts Briony back to her thirteen-year-old self, a writer who is attracted to fairy-tales and order. Briony suffers from her an inflated sense of creative genius, going even as far as to refer to herself as "God." Even Briony herself, who is dying, can joy a happy ending in the form of a loving family reunion and successful performance of her very first play. The villains, the Marshalls, appear to be suffering shallow isolation and impotence regardless of their wealth.
In whole, "Atonement" is a book about imagination and storytelling. It demonstrates the great risk of the writer and how dangerous fiction can be, especially when mistaken for history. In short, the book is an examination of the relationship between what is imagined and what is true. When the reader learns of the "many drafts" since 1940, he/she can help but ask him/herself: "Okay then, which is the real one?"
The question left to the reader at the end, is who does Briony seek atonement from? Is it a reconciliation from her reader or an "at-one-ment" with herself?