Are there some transgressions that can never be forgiven? Most societies, as evidenced by the many death sentences and life sentences handed out by courts each year, certainly think so. But what about the offense made by a young girl reacting to something she thinks she understands but really doesn't? Can she be forgiven?

The atonement of that 13-year-old girl, Briony Tallis, sets the stage for Joe Wrights' visual and moving masterpiece "Atonement" based on Ian McEwan's highly acclaimed novel by the same name.

The beginning of the film takes place on a hot summer afternoon at the home of an upper class British family in the English countryside in 1935. At this point the movie is told from two points of view: that of 13-year-old Briony (newcomer Saorise Ronan), a precocious and self-centered aspiring writer, and the viewpoints of her older sister, the glamorous and posh Cecilia (Keira Knightley, ("Pirates of the Caribbean: At World's End"), and the housekeeper's handsome and educated son, Robbie Turner (James McAvoy, "Becoming Jane").

What is a burgeoning romance between Robbie and Cecilia is viewed as something altogether different by Briony who misinterprets a sexual embrace between the two as a violent attack by Robbie on Cecilia. Later that night when Briony's cousin is raped, Briony immediately points the finger at Robbie.

That the word of one little girl is all it takes to ruin Robbie's bright future is a reminder of the unfair class system which ruled British society at the time. Briony's set little face full of pious moral certainty as she looks on while Robbie is lead away by the police is chilling and brilliantly acted by Saorise.

Fast forward five years: Robbie has joined the British Army in order to get out of prison and finds himself behind enemy lines in France after the British have retreated in the face of the German blitzkrieg. Cecilia has cut off all contact with her family, angry at their prejudiced treatment of Robbie, and is now working as a nurse in London.

Briony as well is greatly changed. Gone is the self-righteousness that characterized young Briony. In her place is a broken-hearted young woman (Romola Garai, "Amazing Grace"), living daily with the knowledge that she has ruined two lives and in doing so lost the love of a beloved sister.

Much as she might wish it, Briony finds that she can not undo the harm she caused. Faced with that knowledge, she goes to extraordinary lengths to try to assuage her guilt. Fast forward another 60 years and Briony is still bound by her actions as a 13-year-old girl. Elderly Briony is portrayed by Vanessa Redgrave ("Evening") who beautifully evinces the heartbreak that can come from a lifetime of regret.

Though the plight of Robbie, Cecelia and Briony takes center stage, the backdrop of World War II can not be ignored either. One of the most stirring sequences of the film depicts Robbie walking dazedly around the French beach at Dunkirk where thousands of soldiers are milling around and dying, waiting to be evacuated.

An equally moving sequence is of Briony, also working as a nurse in London, confronted with the first casualties of war. What remains of her romantic starry-eyed ideals of heroically serving her nation as a nurse are abruptly shattered by the reality that war is ugly and it leaves behind ugly wounds on men who are far too young to have their futures ripped from them.

"Atonement" is rated R for disturbing war images, language and some sexuality and has a running time of 2 hours and 2 minutes.