12-year-old Griffin Campbell and his family move to the small town of Sulphur Springs and take ownership of an abandoned hotel rumored to be haunted by the ghost of a girl who disappeared decades ago. Griffin befriends Harper, a bright-eyed, mystery-obsessed classmate and together, they uncover a secret portal that allows them to travel back in time. In the past, they’ll attempt to uncover the key to solving this unsolved mystery, a mystery that affects everyone close to them.