A more metaphysical atonement lies in her work as a novelist: we realize that we have been reading Briony's own rewriting of the initial events and her careful imaginative reconstruction of Robbie's experiences in the Dunkirk evacuation. She tells of her discovery of the actual rapist (if a rape it was), her decision to retract her accusations and her efforts to make amends with Robbie and Cecilia.

In a final section, set in 1999, the aging Briony, now a successful novelist, learns that she is developing progressive vascular dementia. Soon, her ability to remember and grasp reality will desert her. But she has finished writing her latest version of Robbie and Cecilia's story, the novel we have just read, and can rest.

Her atonement seems complete until we learn that Robbie died in France and Cecilia in the Blitz, and that the (relatively) happy ending we read was simply made up by Briony. Devastatingly, we learn that atonement for an error of fiction has been limited to fictional reparation. The lethal damage it has caused in the actual world is beyond mending . . . unless, of course, we accept the vertiginous truth that the damage described in this novel is itself also no more (or less) than a fiction.