In the cold, unforgiving world of Lis, survival is a currency bought with blood. Kim Taehyung, a ruthless mercenary with a frozen heart, possesses the volatile power of 'O' - a destructive energy system that feeds on life force. When a catastrophic betrayal leaves him left for dead in the ruins of the Mona region, Taehyung's path collides with Jeon Jungkook, a silent, lethal survivor who shares the same rare power. Bound by necessity but divided by mutual distrust, they must navigate a landscape of shifting alliances, corrupt factions, and monstrous entities unleashed by the failing world-core. As the skies of Mona darken, Taehyung is forced to confront a terrifying reality: the very power keeping him alive is slowly consuming his humanity. To survive the onslaught of enemies hunting them down, Taehyung and Jungkook must master the true potential of 'O' before the darkness within them consumes Lis entirely, leaving nothing but ashes.
