Astro Boy is set in a futuristic world where androids co-exist with humans. Its focus is on the adventures of Astro, a powerful robot created by the head of the Ministry of Science, Doctor Tenma, to replace his son Tobio, who died in a car accident. Dr. Tenma treated him as lovingly as if he were the real Tobio, but soon realized that the little android could not fill the void of his lost son.