Three decades after the emergence of 'Samon Syndrome,' a phenomenon whisking youths to fantastical realms, Akatsuki Ousawa, the famed 'Rogue Hero,' relinquishes his serene life in Alayzard to confront fresh trials back on Earth. Accompanied by Miu, the offspring of the vanquished Demon King, he must now safeguard her true lineage by presenting her as his sibling. Enrolling in Babel, a specialized institution nurturing individuals with newfound abilities from alternate dimensions, the duo delves into a realm shrouded in mystery. As they navigate the enigmatic agenda of the school, facing off against a formidable student council, Akatsuki and Miu delve deeper into the covert machinations that threaten both humanity and themselves.