"The Family Upstairs" is a psychological thriller novel by Lisa Jewell. The story revolves around Libby Jones, a young woman who inherits a mysterious house in London from her parents, whom she never knew. As she explores her new home, she uncovers dark secrets about her family's past and the tragic events that occurred there. The narrative alternates between multiple perspectives, including those of Libby, Henry, and Lucy, revealing their interconnected lives. As the characters confront their histories, the tension builds, leading to shocking revelations about love, betrayal, and the complexities of family dynamics.