Jack Linden (Mark Ruffalo) and Hank Evans (Peter Krause) are best friends who both teach at the same university in a small New England town. They both have young children and Jack's wife, Terry (Laura Dern) is close with Hank's wife, Edith (Naomi Watts). But while things appear happy on the surface, there are smouldering pockets of discontent underneath. Financial struggle and domestic boredom has drained the passion from Jack and Terry's marriage, while Hank's numerous infidelities and self-absorption has prompted Edith to find both comfort and sexual fulfilment with Jack...