After conquering the galaxy and reaching its peak, humanity begins to decline due to diminishing resources in the universe. about 500 billion humans return home to earth, leading to a war between various factions for control over the planet. the gaia sanction, an authoritarian government, prevents re-population of earth. captain herlock was part of the elite wing tasked by the gaia sanction to defend earth. his fleet was unbeatable under his command, but he became angry when a diplomatic elite immigrated to earth. he went rogue and attacked diplomats and his own fleet. in an attempt to make earth uninhabitable, herlock released dark matter on the planet, which immortalized him. a hundred years have passed since then, with captain herlock still at large and in control of the arcadia. the gaia sanction continues its plans for earth's control while hiding its true state. however, captain herlock is preparing for a final showdown with them to determine the fate of the world!