When Harold Fry nips out one morning to post a letter, leaving his wife hovering upstairs, he has no idea that he is about to walk from one end of the country to the other. He has no hiking boots or map, let alone a compass, waterproof or mobile phone. All he knows is that he must keep walking to save someone else's life.

Andy Barber has been an assistant district attorney in his suburban Massachusetts county for more than twenty years. He is respected in his community, tenacious in the courtroom, and happy at home with his wife, Laurie, and son, Jacob. But when a shocking crime shatters their New England town, Andy is blindsided by what happens next: His fourteen-year-old son is charged with the murder of a fellow student.

On a warm summer morning in North Carthage, Missouri, it is Nick and Amy Dunne’s fifth wedding anniversary. Presents are being wrapped and reservations are being made when Nick’s clever and beautiful wife disappears from their rented McMansion on the Mississippi River. Husband-of-the-Year Nick isn’t doing himself any favors with cringe-worthy daydreams about the slope and shape of his wife’s head, but passages from Amy's diary reveal the alpha-girl perfectionist could have put anyone dangerously on edge.