A ten-year-old boy boards a cosmic train to become a robot so he can murder the man who killed his mother. The Galaxy Express 999 is patient enough to let that revenge fantasy breathe across an entire film, never rushing the weight of what immortality actually costs. By the time Tetsuro reaches his destination, the show has already dismantled why he wanted to go there in the first place.
A boy named Tetsuro carries grief like a weapon. Count Mecha murdered his mother, and now revenge consumes him in a future where the wealthy trade flesh for immortal machine bodies. The poor scrape by on polluted streets while the rich ascend toward robot immortality on distant planets. When a mysterious woman named Maetel appears and offers him passage aboard the Galaxy Express 999, a legendary starship that travels between worlds, Tetsuro seizes his chance. She promises him a free ride to the robot planet where he can claim the body and power necessary to destroy the man who took everything from him. But as the train hurtles through the cosmos, carrying them between strange stations and encounters with unforgettable travelers, Tetsuro discovers that the journey itself transforms him in ways he never anticipated. The cost of becoming something new might demand more than he's willing to sacrifice. The question shifts from whether he can achieve revenge to whether he still wants to once he understands what it would make him become.