Astro Boy is a science fiction series set in a futuristic world where robots co-exist with humans. Its focus is on the adventures of the titular "Astro Boy" (sometimes called simply "Astro"), a powerful robot created by the head of the Ministry of Science, Doctor Tenma (aka Dr. Astor Boyton II in the 1960 English dub) to replace his son Tobio ('Astor' in the 1960s English dub; 'Toby' in the 1980s English dub and the 2009 film), who died in a car accident. Dr. Tenma built Astro in Tobio's image and treated him as lovingly as if he were the real Tobio, but soon realized that the little robot could not fill the void of his lost son, especially given that Astro could not grow older or express human aesthetics (in one set of panels in the manga, Astro is shown preferring the mechanical shapes of cubes over the organic shapes of flowers). In the original 1960 edition, Tenma rejected Astro and sold him to a cruel circus owner, Hamegg (Cacciatore the Great in the '60 English dub).
After some time, Professor Ochanomizu, the new head of the Ministry of Science, noticed Astro Boy performing in the circus and convinced Hamegg to turn Astro over to him. He then took Astro as his own and treated him gently and warmly, becoming his legal guardian. He soon realized that Astro was gifted with superior powers and skills, as well as the ability to experience human emotions.
Astro then is shown fighting crime, evil, and injustice. Most of his enemies were robot-hating humans, robots gone berserk, or alien invaders. Almost every story included a battle involving Astro and other robots. Once, Astro actually took on the US Air Force, stopping it from bombing some peaceful innocent Vietnamese villagers (this was a time-travel episode, in which our hero went back from the 21st century to 1969).