The house in Poplar Wood

The Vickery twins, Lee and Felix, live in a house in Poplar Wood, where, because of the "Agreement," their mother serves Memory, and their father assists Death, and only Lee is allowed to leave the house, except for Halloween; but when a local girl is murdered, Gretchen Whipple, daughter of the mayor, offers the boys a deal--help her solve the crime and she will help them break the Agreement, and regain their freedom.