Bernard Berkman (Jeff Daniels) is a once great novelist whose career has gone into a slow decline as he spends more time teaching and less time writing. His wife, Joan (Laura Linney), meanwhile, has recently begun publishing her own work to widespread acclaim, which only increases the growing tension between them. One day, Bernard and Joan's two sons - 16-year-old Walt (Jesse Eisenberg) and 12-year-old Frank (Owen Kline) - are told that their parents are separating, with Bernard renting a house on the other side of Prospect Park from their home in Park Slope, Brooklyn. As the parents set up a schedule for spending time with their children, Walt and Frank can hardly imagine that things could get more combative between their folks, but they do, as Joan begins dating Ivan (William Baldwin), Frank's tennis instructor, and Bernard starts sharing the house with Lili (Anna Paquin), one of his students. Meanwhile, the two boys begin taking sides in the battle between their parents, with Walt taking after his father and Frank siding with his mother.