Peru trained under Gaston Roux, a legendary maker of masks that grant power to whoever wears them. Taken over by the Mask of the Warrior God, Peru kills his friends and even his own master without meaning to. To keep such a tragedy from happening again, he vows to destroy every mask Gaston made, now scattered around the world. Traveling as a mask merchant who can craft masks of his own, he arrives in a city with an eerie atmosphere and meets Sonah, a mysterious young girl. Along the way he makes new friends, faces powerful enemies and confronts the sins he has committed, hoping one day to atone for what he did to his master. The series is a supernatural action drama built around battles between mask wielders.