With her 11 year-old son Claude (Zane Pais) in tow, Margot (Nicole Kidman) is anxiously traveling to her childhood home to attend the wedding of her sister, Pauline (Jennifer Jason Leigh) to unemployed oaf, Malcolm (Jack Black). An egotistical, self-absorbed, judgmental woman, Margot instantly disapproves of the union, going about her business wrecking lives as she enjoys the weekend festivities. Soon enough, her poison is rebuffed by family and lovers (Ciaran Hinds), leaving her in a state of panic as she gradually reexamines her own life.

Baumbach can author screechingly hilarious material for his characters, but he's at his most persuasive when he wades into behavioral muck. "Margot" is an extension of the observational diamonds he unearthed in "Squid," retreating even further into the lethal nuance of sisterhood and the fatigue of know-it-alls. "Margot" is a brutal, wonderful movie; it draws blood in the manner it dramatizes conflict and humiliation with front row curiosity, yet remaining one of the most satisfying comedies of this year.

Holding hands with his idols Bergman and Rohmer, Baumbach attacks "Margot" with an open range, documentarian style, as though he's capturing these characters in their natural state of loathing, without the assistance of artifice. A character study, Baumbach's script careens wildly shadowing Margot's tour of destruction, studying the impulses of the characters as they blurt out horrible things to each other, as if basic communication was an open invitation to insult each other. Margot is embarrassed by her sister's attraction to Malcolm, equally repulsed and dependent on her son's attention, and finds herself drawn to conflict as a means to reinforce her own intelligence. These are broad strokes, but "Margot" is striking in the way it uses the shrillness of the character to examine the larger scope of cancerous domestic ties and compulsive self-satisfaction.

Nicole Kidman brings this character to life as a fountain of hypocrisy, and it's a lovely performance that constantly develops over the course of the picture. Baumbach places an enormous amount of trust in his talent, and that permissiveness takes the picture in a million delirious directions, some moody and vile, others mortifying, but he's willing to follow wherever they lead. The film boldly asks the audience for their participation in the processing of motivation; love or hate these people, but it's tough to argue their humanity and unnervingly recognizable behavior.

Baumbach works his cinema verite muscles to a point of soreness, but the effort results in an unexpected delight. Perhaps "Margot at the Wedding" isn't for the caustic sibling squeamish, but it's a wonderful picture, informed with a powerful sense of honesty and comedy that that's so robust and exhilarating, it could cause whiplash.