Set in the futuristic Metro City, Astro Boy (Atom) is a young robot with incredible powers created by a brilliant scientist in the image of the son he had lost. Unable to fulfill his creator's expectations, Astro embarks on a journey in search of acceptance, experiencing betrayal and a netherworld of robot gladiators, before returning to save Metro City and reconcile with the father who rejected him.

The interplanetary spacecraft Galileo II carries Atom and his friends to Titan, a satellite of Saturn. However, what awaits them when they arrive there is an attack from an unknown entity. What appears is a mechanical life form called "Igza" that wants to destroy humans. The battle between Atom and Igza unfolds in the far reaches of space.