Young Harlock wo Oe! Cosmo Warrior Zero Gaiden

Pirates have kidnapped Zero in an attempt to finally defeat the notorious Captain Harlock. Harlock is bound by a promise to his friend Toshiro to protect his lab on a strange mushroom planet. Fates collide as Zero, Harlock, Sylviana and the pirate Hunter all pursue their own agendas during one decisive battle.

(Source: Anime News Network)