A ten-year-old orphan boards a train that stops at dying worlds, each one teaching him something about what it means to stay human when everyone else is buying immortality. The Galaxy Express 999 moves slowly enough to break your heart at every station. Tetsuro's real journey isn't toward a mechanical body, it's learning why mortality, loss, and the people you meet matter more than forever.

A train crosses the stars, and a poor boy boards it in search of immortality. In a distant future where people can live forever in mechanical bodies that only the rich can afford, ten-year-old Tetsuro Hoshino sees his mother shot down by the machine-man Count Mecha and is himself left close to death. He is rescued by Maetel, a mysterious tall, blonde woman who looks strikingly like his mother. She offers him a pass on the legendary Galaxy Express 999, asking only that they travel together. Those who ride the train to the end of the line are said to receive a mechanical body for free, and with it eternal life. Alone and penniless, Tetsuro jumps at the chance. As the train carries them across the solar system and beyond, the pair visit many strange planets, and danger waits at every stop in this sci-fi adventure drama.