Durant la Segona Guerra Mundial, Rasputin va enviar des de l'infern a la Terra un dimoni anomenat Hellboy per acabar amb la humanitat. Els aliats van aconseguir reconduir els seus poders extraordinaris cap al bé i convertir-lo en un heroi que lluita contra les forces del mal.
Destructive monsters from the Mato dimension threaten the earth, while women gifted with powers from Peaches try to stop them. But to save the world, Yuuki must be willing to become Chief Kyoka's servant both on the battlefield and at home.
Japan, 2019, just before the dawn of a new era. Suddenly, a rift to another dimension appears in the sky, revealing an alternative world "Shinkoku Nippon," with the sky and the earth upside down. This parallel world keeps the former militarism, with its era being Eternal Showa. The military invades the real Japan with giant humanoid robots called "GARANN" and their gas weapons "GENMU", rendering our modern weapons ineffective. "Shinkoku Nippon" instantly seizes the government and achieves de facto conquest of Japan. The new era, "Reiwa," has not arrived for Japan.
