When Fanny Morris's marriage breaks up she takes a sabbatical from her job and moves into her grandmother Georgia Rice's old house in Vermont. Georgia had been like a mother to Fanny; now, twelve years after her death, it is left to Fanny to decide what to do with her house. In this house in the mountains, Fanny's disappointment in her own marriage is thrust into new relief, as she recalls the courtly romance between her grandparents, and their long, loving life together.

Unfolding in tandem with Fanny's present day life in Georgia's house is Georgia's own story, far different from the one Fanny is imagining. This line of the novel takes us from Georgia's childhood in Boston at the turn of the century, which is brought to an abrupt end by her mother's death and the responsibility, which falls to Georgia, of caring for her two young siblings and her father; to her first encounter with the young doctor whom she will later marry, the tragic misunderstanding at the heart of their relationship, and the lie that seals their fate.

As the stories of Georgia Rice and her granddaughter Fanny Morris begin to converge, the questions at the center of The World Below rise steadily to the surface: how vast, in a marriage, is the gulf between appearance and reality? Can true love grow out of a lie? What compromises and losses, secrets and betrayals, can a relationship sustain, and still be redeemed? A tour de force from one of America's most beloved novelists.