If Kenneth Lonergan's Margaret, his first film since You Can Count on Me, establishes anything it is that unless we can acknowledge responsibility and forgive ourselves for any real or perceived wrongdoing, we are caught in an endless cycle of denial and recrimination, potentially causing great damage to ourselves and others by internalizing our guilt. The title is derived not from a character in the movie but from the poem Spring and Fall: To a Young Child, by Gerard Manly Hopkins which is read in class by English teacher John (Matthew Broderick). It is a poem addressed to a child named Margaret that seeks to comfort her cries "over the lovely golden leaves of the autumn forest, all fallen to the ground." If you think Matt Damon looks thin and others have gotten younger, it's only because the film was completed in 2005 but held up for six years in legal battles over its length, which was finally cut by one-half hour. Margaret centers on Lisa (Anna Paquin), a bright but self-absorbed teenage student at a New York private school. She is grieving after a bus accident she witnessed that caused the death of a pedestrian (Allison Janney). It was an accident that was mainly caused by her distracting the driver (Mark Ruffalo) to try and ask him about his cowboy hat, a distraction that caused him to run a red light.

Beating herself up for giving a false statement to the police because she didn't want to get the bus driver fired, Lisa takes out her anger on those around her. One of her easy targets is her mother Joan (J. Smith-Cameron), a stage actress who is already nervous about a new play she is starring in and a new boyfriend Ramon (Jean Reno). Growing more shrill each day, Lisa is a disaster waiting to happen and her school classmates and her teachers are not spared from her acrimony, especially Mr. Aaron (Matt Damon) who is teased into a compromising situation.

Her behavior becomes increasingly inappropriate as she turns to drugs and sex with an experienced school friend (Kieran Culkin), but these provide no escape from her trauma. Eventually she takes a step in the right direction by contacting Emily (Jeanne Berlin), a close friend of the deceased, the bus driver, and the police detective to amend her original statement; however, it does not seem to help her anguish. The plot lurches in different directions with lawsuits, trips to the opera, and increasingly hostile relationships between the main protagonists, and the film becomes more unpleasant and histrionic as it labors towards its conclusion.

There are some excellent scenes, however, in Margaret and the recital of several poems, a passage from Shakespeare, and scenes from the operas Norma and Tales of Hoffman, pays tribute to the city and culture of New York. One of the best scenes is one in which a highly intelligent student challenges the teacher's interpretation of a passage from Shakespeare, only to be met with a brush off and a reference to the "scholarly consensus," a moment very relevant to debates of the present day. Unfortunately, there are few such moments or likable characters in Margaret, and when Lisa, negating her awakening of conscience, takes out her frustration against the bus driver, the film becomes more of a case study of sociopaths than a family drama. Ultimately, Margaret should have remained on the shelf.