The Final Days of the Underwater City
The 999 reached the planet of Rainbow Sash. All that remained was a single underwater city resulting from a nuclear war. Maetel and Tetsuro went to the hotel, and saw the janitor Tadashi was unjustly dismissed by the manager. Tetsuro left the hotel in disgust and stayed at Tadashi's home. Kumi, the hotel receptionist, appeared, and they witnessed a car crash. It turned out the driver was, Miyoko Ohara, secretary to the governor. She warned them of an imminent earthquake that would destroy the city, and gave them the pass to the escape pods before succumbing from her injury. The 999 also departed, but Maetel convinced the Conductor to stay on the surface in case Tetsuro escaped.
Aired 23/10/1980EP 92 - The Final Days of the Underwater City

Galaxy Express 999
After witnessing the death of his mother and being left for dead at the hands of Count Mecha, ten-year old Tetsuro Hoshino is awakened by a mysterious woman, Maetal. In exchange for only his company, Maetal offers him the ride of his life on the Galaxy Express 999. It is said that those who travel aboard the legendary train to the end of the line can receive a free mechanical body and with it, immortality.
Impoverished and alone, Tetsuro leaps at the opportunity and joins Maetal on a quest that will span the cosmos. As the Galaxy Express 999 makes its way across our solar system and beyond, Tetsuro is drawn deeper into a dangerous universe where peril lurks at every stop.
(Source: Discotek)