The story revolves around Semi, a girl who travels back in time to prevent evil forces from using the magic cube.

The story tells the tale of Semi, a bright girl who goes in a magical time journey with the genius teacher Wai, in order to prevent the evil X from utilizing the powers of the magic cube for evil. Along the way, Semi and her math school friends run into history and math problems that they must solve with logic and wit.—MyAnimeList