In the mid-21st century, mankind has begun the exploration of space, and one company, Planet Catcher Corporation, has pioneered capturing asteroids and comets to mine the resources within them for use on Earth. On one such asteroid, Tortatis, lives 12-year-old Nanbu Ushiwaka - the only child ever to be born in space and survive. But survival itself is no longer guaranteed - a military satellite triggers a disaster during a operation to capture Halley`s Comet, and Ushiwaka and his fellow colonists must find a way to survive when both their country and their company abandon them. Can they escape before the nuclear reactor on the asteroid melts down? Or are they doomed to die as they lived, among the stars?

Side stories released exclusively on DVD.

Dr. Hell and his Mechanical Beasts are back, and they're more dangerous than ever before. Kouji Kabuto and Tetsuya Tsurugi fight a fierce battle against these hellish machines, which are under the command of Baron Ashura. Unfortunately, they are defeated, with Kouji's Mazinger Z being captured and Tetsuya's Great Mazinger seriously damaged by the enemy. The devious Dr. Hell quickly converts the captured robot into Ashura Mazinger and uses it to attack the Photo Power Lab. At the same time, Kouji is missing in action, which leaves Testuya to defend the lab in the damaged Great Mazinger. But the forces of Dr. Hell are too strong, even for a brave pilot such as Tetsuya, and all seems to be lost. The battle seems to be drawing to a close, until an overpowering blast fired by an unknown robot destroys the entire Mechanical Beast army. Could this mysterious robot be the legendary Mazinkaiser, and who is piloting it?

Naoki Kuzumi, a junior in high school, had lost his parents in an accident five years ago, and is living with his aunt, uncle, and cousin Matsuri. He always thought his life was ordinary, besides the fact that he can't remember what happened in his youth. One sunny day as he is taking a nap on a bench, a redheaded girl -- Mikoto -- literally falls on him from the sky. For some reason, she thinks he's her younger brother. Naoki's time period is a temporal shelter for those in the future, when many are suffering from an incurable disease. When she heard her younger brother Yuusuke had been taken to Naoki's time, Mikoto herself had gone back in time.