When 18-year-old Taiyō Myoga is attacked by a monstrous cat spirit after his college entrance exams, his world turns upside down. Sent away to Kyoto, he discovers he's descended from Japan's Imperial bloodline and is thrust into a hidden world of magic, mythology, and danger. At a secret dojo, Taiyō trains to become an Imperial Samurai, sworn to protect Japan from supernatural threats. But his family's disgraced past makes him an outcast, and when the three legendary Imperial Regalia go missing, all eyes turn to him. Accused of theft and desperate to restore his family's honor, Taiyō embarks on a perilous quest to recover the sacred relic. With the help of Hanako, a fierce shrine maiden hiding her own secrets, and Satoru, a brilliant but reclusive roommate, Taiyō must navigate a treacherous landscape of gods, demons, and ancient grudges. As dark forces gather and long-buried truths come to light, Taiyō will need more than just skill with a blade to prevent a catastrophic war between the mortal and spirit realms.