In a world where robots cannot kill humans, a bizarre murder case is reported. Europol's robot detective Gadget is in charge of the investigation, but no trace of human involvement is found at the crime scene, and the case is at a stalemate. On the way to find the truth, Gadget suddenly discovers that the ruthless character he has to deal with is the most evil embodiment of hatred in history, and the other party is bent on destroying the world... The drama is adapted from Tezuka Osamu's work "The Strongest Robot on Earth" and the manga "PLUTO" re-interpreted by manga artist Urasawa Naoki.