The strongest hero who saved the world, become the enemy of the world. A 13-year old boy was summoned to a different world, and fought for 3 years as a hero. In the end, he was betrayed by his master, the person he trusted most. Five years later, the hero who was supposed to have died was summoned once again. Throwing away his past as the defiled hero, he registers with the guild as an adventurer. Concealing his background, he travels in this new, chaotic world. Called a monster, the strongest hero… Attacked by his former companions… “I will become your enemy.” To save the world, he will become the enemy of the world.