Kenneth Lonergans Margaret feels both incomplete and uncut. What lives on the screen arrives like the bullet points of a much larger, much grander, impossibly longer version of the same basic story: a pseudo-intellectual teenage girl whose life, full of adolescent semi-dramas, is turned upside down when she witnesses/causes a tragic bus accident that takes a life. In the aftermath of the incident, she makes a mistake shell spend the rest of the film trying to reconcile. With everyone. The bus driver (Mark Ruffalo); her mother (J. Smith-Cameron); her amiably neglectful father (Lonergan); the victims best friend Emily (Jeannie Berlin); her young, attractive private school teacher (Matt Damon) and so on and so on.