After humanity's dominance over the galaxy peaks and starts to wane due to dwindling resources, around 500 billion individuals return to Earth, sparking a war among different human factions vying for power. The Gaia Sanction, an oppressive regime, blocks further repopulation of Earth. Captain Herlock, once a loyal defender under the Gaia Sanction, rebels against them when they allow privileged elites to settle on Earth. In a drastic move, he turns against his own fleet, unleashing dark matter to render the planet uninhabitable while inadvertently gaining immortality. A century later, Captain Herlock, now a legend, commands only the Arcadia ship. As the Gaia Sanction schemes in secrecy to control Earth, Captain Herlock readies for a final epic confrontation that will decide the planet's destiny.