In 2017, Son Oh Gong and Ma Wang are locked in conflict as they search for a true light in a world overrun by evil. Years earlier, Son Oh Gong made a contract with a young girl named Seon Mi, promising to help her whenever she called in exchange for his freedom.

Now grown, Seon Mi crosses paths with Son Oh Gong once more, reigniting their bond. Bound by the old promise, Son Oh Gong becomes her reluctant protector in a dangerous, fate-driven world.