Perky, spoiled blonde 12-year-old Ruridou Doris is an heiress to one of the largest advertising companies in Japan. So, naturally, she's sent to one of the most prestigious schools in Japan, one so large that it has its own subway system, and even a stadium for mecha combat. It just so happens that Doris, like one out of every ten people in her world, is a panzer, someone who…