Disguising himself, as a human boy, Astro Boy goes undercover to investigate a drug trade. Some criminals have developed a drug called Yellow Horse, when injected it causes people to dance and make people want more. Professor Ochanomizu has been captured by the drug ring and injected. They try to blackmail him into helping them produce and distribute the drug in exchange for another shot. But Astro is able to pose as a Yellow Horse addict thanks to an artificial skin that makes it look like he is injecting it into himself. He tracks down the headquarters and leads the police to arrest them all. The Professor goes to rehab along with all the addicts for detoxification.