Amelia has everything: two perfect children, a successful husband who loves her and a big house. So why does she wake up one morning with a distaste for her daughter and a strange attraction to James, a dad she sees in the playground at drop off? James has everything too: a happy marriage to fellow academic Alice and two young children. When his wife's star begins to rise, James starts to look for a way to cure his sense that something vital is missing from his own life. As all of their lives overlap, the repercussions threaten to blow both families apart.