There is no other choice but to summon heroes to protect the [Heavenly Core] a ???-Class item against the Demon King "Arnus" and its horde of monsters. Unfortunately, Aizawa Yuuki, was chosen to be transferred unto this world and bestow its power to protect it. But, God had mistakenly summoned him without a proper location. And Yuuki was randomly summoned and accidentally absorbed the Heavenly Core. Let the journey begin!