The Platonic Heart is a jewel that, as an old urban legend has it, will grant any wish to whoever collects it. Only a select few may join the hunt for it, and high school junior Aya Iseshima becomes one of eleven girls and women competing. Her easygoing life turns violent when she stumbles into a secret martial arts tournament fought between women, where clothes get torn apart in bout after bout. Aya faces opponents ranging from teachers to flight attendants, knowing that anyone who loses disappears and is never heard from again. The OVA pairs action with heavy ecchi content across five episodes.