When Grace's mother, Lucy, dies she wants to move on in her life, not become stuck in domestic routines with her two teenage children. But when a strange, elderly man turns up at the funeral, her life takes an unexpected turn. For Jack, the death of his wife pushes him to discover what had happened to the real love of his life, Lucy. He is haunted by what might have been, while Grace worries about who appears to be stalking her now. Gradually, the two families' lives entwine and they discover that the past shapes the future in often surprising ways.