Galerians: Rion (ガレリアンズ：リオン Garerianzu: Rion) is a computer-generated OVA based on the original game, Galerians.
A 14-year-old boy, named Rion Steiner one day wakes up in a hospital observation room. Having no memories of his past or how he got there, a mysterious voice of a girl begs him to save her. While he is trying to escape, he discovers he has psychic powers.
Using this ability he kills off the staff and hospital security. He finds out he needs to take drugs for not losing control; using different drugs gives Rion a different ability. Rion discovers that in the hospital, they're having human experiments, named `G Project,` related to his powers. He also finds out information about himself.
Having finally escaped, he goes home, memories coming back to him, but interrupted by G Project experiments/monsters and a Galerian named Birdman. He soon finds the girl who called out to him is a childhood friend named Lilia, who is also the daughter of Dr. Pascalle, a colleague of Rion's father, who wants to help Rion destroy an artificial intelligence named Dorothy. Dorothy was a super computer program made to serve humans. However, she started to wonder why she should help humanity. One of her creators, Dr. Steiner, told Dorothy about the existence of God and how humans must serve their creator as she must serve humans. Dorothy responds to this by starting a secret program to create super-humans` named Galerians, plotting to use them to kill off humanity and rule Earth being served by her Galerians. Throughout the story, the Galerians are also after Lilia, as she has a virus program implanted in her brain as a safeguard against Dorothy.
Dorothy sends her Galerians after Rion and Lilia. It's up to Rion to kill the Galerians, destroy Dorothy and save humanity. Rion comes face-to-face to the last Galerian Cain, who is a clone of the real Rion, and he finds out the horrible truth: he himself is a Galerian — a clone of the real Rion who died a while ago. Killing off Cain, Rion confronts and battles Dorothy and uses all his powers to destroy her.
Lying in Lilia's arms, Rion says his last words and dies. In the end, the scene changes. In a completely white area, Rion is seen sitting down with his head low and finally disappears into thin air, symbolizing his death.
- Scenes from the movie are used in the beginning of Galerians: Ash, recapping events from the first game.