Jae-Hyun inherits the mysterious Abyss blade once wielded by his grandfather, Kang Jin-Ho. When dangerous rifts begin appearing, he discovers they are connected to an ancient secret. As forgotten beings awaken and powerful factions emerge, Jae-Hyun is forced to uncover his grandfather's hidden past. But the deeper he enters the Abyss, the more he realizes that his inheritance may be a curse rather than a gift.