"Galaxy Express 999 for Planetarium" is a condensed adaptation of the iconic "Galaxy Express 999" series, designed specifically for planetarium screenings. The story revolves around Tetsuro Hoshino, a young boy living in a dystopian future where humanity has achieved immortality through mechanical bodies. Tired of his impoverished life and driven by the desire to avenge his mother’s death at the hands of the mechanized noble Count Mecha, Tetsuro dreams of boarding the Galaxy Express 999, a space train that travels to the planet Andromeda, where he can obtain a free mechanical body.

Tetsuro’s journey begins when he encounters Maetel, a mysterious and elegant woman who offers him a ticket to board the Galaxy Express 999. Together, they embark on an interstellar voyage across the galaxy, stopping at various planets and encountering a wide array of characters, each with their own stories and struggles. The episodic nature of the narrative explores themes of humanity, mortality, and the consequences of technological advancement. Tetsuro’s interactions with the passengers and inhabitants of these planets gradually shape his understanding of life, death, and the true cost of immortality.

As the journey progresses, Tetsuro learns more about Maetel’s enigmatic past and her connection to the mechanized empire. The relationship between Tetsuro and Maetel evolves, blending mentorship, companionship, and a deeper emotional bond. The narrative builds toward a climactic confrontation with Count Mecha, where Tetsuro must reconcile his desire for revenge with the broader philosophical questions raised by his journey. The story concludes with Tetsuro making a pivotal decision about his future, reflecting the series’ central exploration of what it means to be human in a world dominated by machines.