At the conclusion of *Arcadia of My Youth*, Captain Harlock and the crew of the spaceship Arcadia are banished from Earth. The planet, along with many others in the galaxy, has been taken over by the Illumidus, a hostile humanoid race that destroys, enslaves, or devastates nearly every habitable world they encounter. In *Endless Orbit SSX*, Harlock battles the Illumidus while searching for the mythical Planet of Peace, a place where all peoples of the universe can live freely and without war.