After the cataclysm hit, Earth was plunged into the Age of Gates and Hunters. Abominations ran rampant, bringing death and destruction wherever they went. The system, which came with the gates, gave humans a fighting chance to resist the apocalypse. Kei, who had grown up amidst the conflict between humans and gates, strives to become a pro hunter and live a lavish life, but the world has other plans for him. Follow Kei's journey as he faces tough trials and tribulations, and discovers the truth about the gates and this world.