A sci-fi retelling of Wagner's "Ring of the Nibelungen", starring Captain Harlock. Alberich has stolen the Rhinegold from a planet at the center of the universe and, with it, has forged a ring of untold power, possibly acquiring with it the ultimate power to conquer the universe. Captain Harlock becomes involved in this struggle when he comes into contact with Alberich's sister named Mime, and engages into an adventure with the fate of the universe hanging on the balance.