The story takes place on Southern Cross Island, where 20 "cybodies" - mysterious mecha devices that can grant their pilots incredible abilities - are hidden underground. The cybodies are sealed and guarded by the Sacred Maidens. The organization "Shining Star Cross" is researching ways to access and claim them for themselves. To conceal their sinister plan, they operate under the guise of educational institutions, where supposedly ordinary young people are studying. In reality, most of the teachers and their students lead double lives.