After cruelly executing the wicked ghosts that killed his parents, a young boy named Lee-se is branded as a monster by his village. Having lost all attachment to life, Lee-se meets Mong-ryeon, a goblin and ghost hunter, and adopts a new goal: to exterminate all ghosts from the world. As they begin living together, Mong-ryeon discovers a unique trait in Lee-se and sends him to 'Daemudo,' a cultivation sect known as the executioners of the cultivation world.