Once every half-century, the enigmatic Hourai island materializes, sparking tales of eternal youth or impending catastrophe. Inuyasha and his companions intervene when a young half-demon named Ai seeks refuge from Hourai's dangers. Ai implores Inuyasha for help in rescuing her captive friends from the ruthless Four War Gods, ancient foes of Inuyasha. As they venture to Hourai, they uncover a grim reality: the island's few remaining children are earmarked as sacrifices to empower the malevolent deities. Bound by a sinister magic, escape seems impossible for these doomed youths. To stand a chance against the formidable Four War Gods, Inuyasha's group must unite their strengths and embark on audacious strategies that demand unwavering teamwork.