After the death of his mother at the hands of the evil robot Count Mecha, young Tetsuro has become a delinquent street urchin who dreams only of revenge. 
Tetsuro lives in a far future world in which humans have the choice to travel to another planet where they can exchange their bodies for immortal, robotic counterparts. His goal is to someday acquire (through theft) enough money to board the Galaxy Express 999, a train which is capable of traveling through space, and which will take him to the planet of robots. 
One day, after escaping from the police, he meets the beautiful Maetel, who resembles his mother. She offers to take him on the Galaxy Express 999 to get a robotic body and to get revenge on Count Mecha. Along the journey, the two meet many varied people (including Captain Harlock and Queen Emeraldas), and Tetsuro learns what it means to be human. 
(Source: Anime News Network)

The year is 2977. Mankind has become complacent and stagnant. All work is done by machines, while humans spend all their time on entertainment. But when a mysterious invader from the stars catches Earth unawares, only the legendary space pirate Captain Harlock and the crew of the Arcadia have the will to stand against them. 
(Source: Anime News Network)

Two years after the events in Galaxy Express 999, Earth has become a battleground. Tetsuro, older and fighting the Machine People, rejoins Maetel aboard the GE999.

Tetsuro Hoshino is a young street urchin who desperately wants to replace his human body with an android body, which would grant him immortality and the social freedom the androids have. Normally this is incredibly expensive but it has long been rumoured that if you board the Galaxy Express headed for the Andromeda Galaxy, at the end of the line is a planet where they are given out for free. After seeing his mother murdered by an Android Count, he has no reason to remain on his home planet and nothing to hold him back. Now, not only seeking the android body of his dreams but also a way to avenge his loss, he begins to search for a way to board the train alone. Then he meets Maetel, a mysterious woman who offers him a ticket aboard the train if he will be her companion for the journey. Their journey will take them to planet after planet, each strange and new, and each stop along the way being an opportunity for Tetsuro to reflect on being human, human actions, and the prospect of immortality. During their travels Tetsuro and Maetel meet, amongst others, Emeraldas and Harlock. 
Note: The first cycle was released from 1977 to 1981 and spans volumes 1-18.

After witnessing the death of his mother and being left for dead at the hands of Count Mecha, ten-year old Tetsuro Hoshino is awakened by a mysterious woman, Maetal. In exchange for only his company, Maetal offers him the ride of his life on the Galaxy Express 999. It is said that those who travel aboard the legendary train to the end of the line can receive a free mechanical body and with it, immortality.

Impoverished and alone, Tetsuro leaps at the opportunity and joins Maetal on a quest that will span the cosmos. As the Galaxy Express 999 makes its way across our solar system and beyond, Tetsuro is drawn deeper into a dangerous universe where peril lurks at every stop. 
(Source: Discotek)

After a meteor hits Earth, traitor forces have (for all intents and purposes) taken over, and the people are suffering. In the chaos, a boy named Tetsuro Daiba, who had lost his parents in the meteor hit, is paid a visit by Mello, a mysterious woman appearing in a bright light. When Daiba comes to, he finds itself in a spaceship infirmary under observation. Stealing a fighter that he didn`t know how to pilot (until he tried it), he breaks out, flying like a total pro. 
He was able to remember how to pilot from his DNA memory... and to find out more, his doctor friend takes him to his secret underground lab, in which he acts as a professor to find out ways to stop the traitor regime. When the forces invade to take him back, a girl named Rei Yuuki mysteriously shoots down their entire carrier with only a fighter jet! Apparently, both have mysterious powers that the enemies want, which may or may not be connected to their being the only two known survivors of the meteor impact. 
While looking for a third survivor (which turned out to be a cat), the two are taken by force to Queen Photon (ruler of the traitor regime), who claims that she is out to SAVE the Earth from those who sent the Meteor. The two don't know whether to believe her or Mello until the (telepathic) cat breaks them out of the Queen's sealed chamber, and Mello comes to straighten things out. That's when the two (er, three) of them make a choice... Stay on a planet that can't support their advanced race, or strike out into the unknown of space? 
(Source: Anime News Network)

Maetel abandoned her mother and her home planet, the doomed and frozen La Metal, where people must become cyborgs to survive. When she is beckoned to return, her options seem slim: follow her mother's path (and with it a robot mind and the contempt of all humans), or run away and fight with humans against the machines. Yet, she is not without comrades and defenders. If she can accept the friendship of beings of metal who desire peace, and oppose those who think being made of flesh and blood is enough to make one human, she may still have a chance to find her own path. 
(Source: Anime-Planet)

Tags