After conquering the galaxy, humanity has reached its peak and is now in steady decline. Universal resources are dwindling, and approximately 500 billion humans begin returning to Earth. This triggers a war among various human factions for control of the planet. Eventually, an authoritarian regime called the Gaia Sanction halts the repopulation of Earth. Captain Herlock was a member of the Elite Wing, tasked by the Gaia Sanction with defending Earth. His fleet was unstoppable under his command. However, the Gaia Sanction permits a diplomatic elite to immigrate to Earth, which infuriates Herlock. He goes rogue, firing on both the diplomats and the rest of his fleet. He decides to unleash dark matter on the planet to render it uninhabitable, but becomes engulfed in it himself, which immortalizes him. One hundred years have passed, and the legendary Captain Herlock remains at large, controlling only the Arcadia. The Gaia Sanction continues its plans to control Earth, while concealing the planet's true condition. But Captain Herlock is preparing for one final showdown with them, which will determine the fate of the world!