Atlas Forever

S1, E43: The Defense Force formed against the assaults on airships in the solar system attacks Atlas's crystal castle. Knowing that such assaults are not the work of Atlas and Atlas is his own brother, Astro is deeply shocked. Unidentified flying saucers appear over the earth. Astro fights against the invaders together with the defense force; however, the force is damaged severely. Astro pleads Atlas for help. Atlas, acknowledging Astro as his own brother, gets in his crystal castle, which then turns into a huge black hole. Swallowing the enemy's mother ship, the castle itself disappears somewhere.