High school student Hajime Nagumo is bullied by some of his classmates because of his relationship with the class idol, Kaori. When he and his entire class are transported to a fantasy world by the god Ehit, all of his classmates gain powerful magical abilities, while Hajime only gains basic alchemy magic to transform solid materials, an ability commonly found in artisans and blacksmiths. During a dungeon raid , Hajime is betrayed by one of his classmates and thrown to the bottom of the dungeon . He survives the fall and creates weapons to escape the dungeon and become stronger. Feasting on monster flesh changes his personality. On his journey, he encounters the imprisoned vampire Yue, who is later joined by the rabbit-eared Shea, the depraved dragon Tio, and others. At the end of the dungeon, Hajime discovers Ehit is a tyrant who has twisted the world to his own advantage. He has made it his goal to conquer all the dungeons in order to acquire artifacts used to return them to their original world.