Ms Maya Lin was a regular school girl until she was summoned by the three arch mages of Rosen into their world to help them fight the demon army. She then learned how to create and cast spells, and after a while became good at it. But as her foremost wish was to go home to her world, the three arch mages constructed a dimension gate to send her home and decided to fight the demon army by themselves.

A year later, though, a dimension gate opened again. Enter the Great Witch.