When 13 year old Katie Hartley moves into a century old house in Benton, Wisconsin, the only challenge she thinks she'll face is making new friends. Upon discovering a mysterious, miniature door in her brother's closet, she instead feels compelled to uncover it's meaning and what lies on the other side. Her compulsion to solve the mystery leads her on a quest involving the disappearance of Marek Manor's original owner Marjorie Marek. Soon she finds that there are others who want the past to remain a secret, and that she is in way over her head.