In a futuristic world where humans can swap their bodies for immortal robot forms, Tetsuro, fueled by a desire for revenge against the sinister robot Count Mecha for his mother's death, leads a rebellious life. His aspiration to reach the distant planet of robots aboard the Galaxy Express 999 drives him to pursue theft as means to secure passage. Amidst a turbulent existence on the run from law enforcement, Tetsuro encounters Maetel, a striking figure akin to his late mother, who extends an offer to accompany him on the interstellar train. Together, they set off on a transformative journey, encountering a colorful array of individuals like Captain Harlock and Queen Emeraldas. Through these interactions, Tetsuro gains profound insights into the essence of humanity.