The Gene Lock is a mysterious and revolutionary technology that boosts human speed, strength, and senses to unprecedented levels. Those who successfully unlock their Gene Lock become "agents" of the new era, with the most exceptional among them known as "Gun Gods." A fierce struggle erupts over this new weapon, prompting the establishment of academies to train agents. As experiments advance and are implemented, alongside coercion from a mysterious race, the world is gradually dragged into the quagmire of war... After the war ends, the mysterious race vanishes, and the agents and Gun Gods become unverifiable urban legends. The two remaining major agent organizations, "Deep Sea" and "Wild Serpent," relocate their bases to the seabed and underground, respectively, maintaining a secluded existence. However, beneath this peaceful facade, danger lurks everywhere.