Kuroji Allenleaf, a young man who has lost all reason to live, is summoned by the gods to an unknown world with the mission of defeating the demons.

However, when he finds himself in the final battle against the demon king, the demon king reveals to him before dying that his new life is nothing more than cruel entertainment for the gods. Upon discovering the truth, the very gods decide to betray Kuroji, accusing him of treason and executing him in front of the entire kingdom.

That was the end of the story, but just when Kuroji thought it was all over, he awakens in a pink room, next to a goddess who offers to help him with his revenge.