In a world of fantasy, a mighty kingdom is brought to its knees by the forces of the ancient demon king and his forces, as a last resort they summoned the thirteen heroes of legend who pushed back the demon king's forces with relative ease and ultimately defeated him in only three months.

Thanks to the grateful kingdom and it's people, the heroes lived a life of pure luxury where every wish of theirs was granted, promised land and a chance to help modernise this world.

Not wishing to taint the pure fantasy world with the struggles of modern life, two of the heroes plot to assassinate the other ten, they must discover the weaknesses and the strengths of the other heroes before the end of the month, when each hero will receive private land and home making assassinating them practically impossible.