In a modern world where there are doors that lead to "dungeons" and "Awakened People" fight to conquer them, the powerless protagonist, Akagi Enma, supports his awakened sister Ayumi who streams her dungeon raids. One day, the siblings are attacked by unknown assailants. When Enma regains his consciousness, the first thing he sees is Ayumi's lifeless body, brutally murdered... Seething with rage and a thirst for revenge, a mysterious demon called Vox suddenly appears before him. Determined to do whatever it takes to get revenge, Enma makes a contract with Vox and obtains a unique ability: "the more he is flamed, the stronger he becomes." In order to hunt down the man who killed his sister, Enma makes a name for himself as a "cancel-worthy" streamer by dealing with the evil the law cannot touch and runs rampant that is found in the dungeons.

"I know this scene all too well…!" Serizawa Eriya, a young man living a life of hardship, is left to support his remaining family member, his little sister, after his father died and mother fell ill. His life, which was already miserable from being scorned and treated almost like a slave by a politician's good-for-nothing son, takes a dramatic turn the day he clears a game called Valhalla's Cradle, his only source of solace. "The game I was so immersed in is becoming a reality?!" From the depths of the ocean, the final dungeon, "The Castle", emerges, and at the same time, monsters begin to ravage every corner of the land. The only way to stop them is to conquer The Castle, and Eriya is the only one in the world who knows how to do it. A story of turning the tables from the very bottom begins to unfold―!