A Good, but somewhat backwards, world is attacked by evil alien space invaders. The most the defenders can do is load their children onto Super Speeder, a gigantic space train, and send it to earth. Along the way it is met by Mazinga 7, earths mighty robot warrior, who is sent to help them reclaim their planet. However the prince of the planet is determined to manipulate the situation so that Mazinga 7 is forced into battle against the invaders home planet. Can the brave pilots of this mighty mecha defeat the seemingly endless enemies they will face?