Director Joe Wright (PRIDE & PREJUDICE) and Academy Award-winning screenwriter Christopher Hampton (DANGEROUS LIAISONS) set themselves a formidable challenge: Adapting Ian McEwan's critically acclaimed 2001 Atonement, a novel that's all about the fact that it's a novel. For the most part, the result is a smashing success, filled with great performances and exquisite production design. But those final moments, in which the true nature of the story is revealed, are an unmitigated disaster. Surrey, England, 1935. On a hot summer's day, 13-year-old Briony Tallis (startlingly accomplished newcomer Saoirse Ronan), an aspiring writer, is preparing to mount the play she's written to commemorate a visit from her older brother, Leon (Patrick Kennedy), and his wealthy chum, chocolate millionaire Paul Marshall (Benedict Cumberbatch). Briony's cast comprises her three cousins — pint-sized twins Pierrot and Jackson Quincey (Felix and Charlie von Simson) and their older sister, 15-year-old Lola (Juno Temple) — who are staying at the Tallises' grand manor house in the wake of a family scandal. During a break in rehearsals, Briony spies her older sister, Cecilia (Keira Knightley), in the midst of an inexplicable, erotically charged encounter with Robbie (James McAvoy), the Cambridge-educated son of the Tallis' housekeeper (Brenda Blethyn). On her way to dinner that evening — after delivering a smutty draft of a letter from Robbie to Celia that Robbie wrote in fit of passion but never intended to send, and which Briony couldn't help but read — Briony again catches Cecilia and Robbie in a compromising position, this time in the library. To her immature but feverish imagination, Briony thinks her older sister is being attacked by the man who, in reality, she really loves. Later that night, when the twins go missing and a member of the household is actually assaulted on the grounds during a search of the property, Briony thinks she knows the attacker's identity. She'll spend the rest of her life trying to undo the damage her false accusation causes on that warm summer night. Like McEwan's novel, Wright and Hampton's adaptation is neatly divided into two halves followed by a short coda, with the second part unfolding in 1940. War has plunged Europe into darkness: Robbie is in France, among the walking wounded retreating toward Dunkirk, and Cecilia is a nurse at a London hospital. Eighteen-year-old Briony (Romola Garai) has abandoned her plans to attend Cambridge — but not her dreams of becoming a novelist — and is a nurse in training, a decision perhaps designed to unburden her conscience of the terrible mistake she now realizes she made five years earlier. Wright and Hampton mix cinematic conventions like flashbacks, dream sequences and non-diegetic soundtrack noise with more literary methods — such as crucial moments being shown from various points of view — in order to bridge the gap between the page and screen and preserve McEwan's profound observations about the nature of truth, storytelling, honesty and lies. The adaptation is smart, lively and deeply engrossing, which only makes that coda, in which Vanessa Redgrave suddenly appears to say everything the film has been subtly showing all along, all the more regrettable. It's a device that's entirely at odds with the inventiveness of the rest of the film, and while it doesn't exactly ruin everything that comes before — the performances, particularly McAvoy's, are too strong for that — it does make it all a bit harder to remember.