12-year-old Lion Campbell as well as his family transfer to the small town of Sulphur Springs as well as take ownership of an abandoned hotel rumored to be haunted by the ghost of a girl who disappeared years earlier. Lion befriends Harper, a bright-eyed, mystery-obsessed classmate as well as with each other, they discover a secret website that permits them to travel back in time. In the past, they'll try to uncover the secret to resolving this unsolved secret, a mystery that affects everyone near them.