 Captain Harlock returns from a deep space mission to find that Earth has been conquered by the green-skinned Illumidas and most of the remaining humans have lost the will to fight back. recognizing his talents, the leader of the Illumidas offers Harlock a position in their military, but he turns it down, chosing instead to lead the life of an outlaw, flying through space as a pirate and helping out the resistance forces of the many planets the Illumidas have conquered.