S1·E1 Ballad of Departure

Tetsuro's mother is murdered while the two of them travel through the snow by the villainous Count Mecha. Before she dies, Tetsuro's mother tells him to go to the planet Andromeda where he can get a machine body and not die like she did. Tetsuro passes out from the cold but is rescued by the mysterious Maetal, who gives him a pass to the Galaxy Express 999 for free under the condition that he will travel with her.