Starring James McAvoy, Keira Knightley, and Romola Garai. Rated 14A. Opens Friday, December 7, at the Park Theatre

A lovingly crafted approach to a striking piece of modern literature, Atonement gets off to a dazzling start and finishes with a satisfying flourish, even if doubts linger in the middle.

Stage veteran Christopher Hampton adapted Ian McEwan's novel for Joe Wright, who also directed the recent, souped-up version of Pride & Prejudice. Wright again uses Keira Knightley, made for period clothing, as Cecilia Tallis, the haughty linchpin between the other major players in this harrowing tale of class and monstrous behaviour initially set in mid-'30s England.

Most crucially, this spoiled daughter of a rich upper-crust clan connects handsome Robbie (James McAvoy), who is crazy about Cecilia, and her kid sister, Briony (played first by Saoirse Ronan and later by Romola Garai), who has a crush on him. Robbie, you see, is the housekeeper's son, but he has been raised as (almost) one of the family. There are definitely issues of trust involved as things break down one hot summer day at their Brideshead-like manor. Briony is confused by the distant sight of her sister arguing with the lad and then plunging into a deep fountain and shooting back out of the water–in the most arresting of many strong aquatic images–like a fiercely shining siren.

Their biggest problem, as we see in fragmented recollections, is less that Robbie has finally professed his ardour to Cecilia than that he has asked Briony to deliver a letter about it. This gives the girl an opportunity to wreak havoc with the information. But Briony's bad reaction sets off a chain of events that reaches its fruition on the beaches of Dunkirk, where the British beat their famous retreat from Nazi-invaded France.

It's here that Wright goes wrong, by placing the mass retreat from France in the summer of 1939 when the war didn't even begin until September. This would have been a very easy title card to fix and the error might have been quickly forgotten if the sequence–surreal on a grand scale initially–didn't drag on so long.

Events finally flash forward to a much later date, and it becomes apparent that this is a tale about the nature of storytelling and the limits of comprehension (and compassion), even by those doing the remembering. The fact that it ends with Vanessa Redgrave as one of the tale's survivors who becomes a famous novelist being interviewed by real-life director Anthony Minghella (The English Patient)–well, draw your own conclusions. But do be careful if you write them down.