So, it must be said...this is a really good movie.  It's a well-crafted film that's beautiful to look at, beautifully acted, and a poignant story. That being said, it's definitely not for everyone. It's slow, overly romantic, and kinda esoteric. 

The movie follows a young man and woman fall in love, only to have their romance cut short by the (false) accusations of the womans' younger sister.  As a young girl, she witnesses events she can't comprehend and horrifically misinterprets them - with disastrous consequences.  The rest of the movie then follows the couple through the course of their lives as they've been affected by that event and the life of the younger sister who realizes the terrible mistake she's made and it's consequences.

The acting in this movie is superb.  Both Keira Knightly and James McAvoy give solid performances as the two leads.  Both of the characters are played with subtlety and at times it doesn't even seem like they're acting.  There is only one scene where this wasn't true and it comes towards the end of the movie when Knightly and McAvoy are confronted by her sister.  Knightly painfully overacts throughout the scene - it's like a parody of how she would have actually reacted - making it a bit laughable.  Other than that, her performance is great.  The standout in the movie is Saoirse Ronan as Briony Tallis the younger sister who sets the tragic events into motion.  For a child actor, she does an amazing job at conveying the complex emotions the role demands.

The way this movie was filmed is, a large part of what makes it so appealing.  It basically takes a scene and then shows it from another perspective in order to illustrate how events can be misconstrued and the consequences that these misinterpretations can have.  This trick adds much more interest to the story and creates a sense of empathy for both view points.  The other standout in this movie is the cinematography.  It is absolutely stunning.  One scene in particular involves James McAvoy's character who is away at war and arriving at a bombed out stronghold of the allied armed forces.  The scene is intricate in composition and is shot in one continuous, extremely long take.  It encompasses many extras and an amazing set that the actors and the camera deftly weave through.  It was an amazing scene both visually stunning and technically impressive.

This movie isn't gonna win over anyone who doesn't already enjoy this genre of film, but it's a really great movie nonetheless.