Mr. Conan informs the Metal Men that Doc Magnus has been abducted and brainwashed by Karnak the Killer, dictator of the nation of Karnia, and is now willingly building an army of robot soldiers for world conquest. The team is devastated when Conan reveals their actual mission is to assassinate Magnus, as Karnak's brain surgery has made their creator insane and beyond rescue. Torn between loyalty and duty, the Metal Men reluctantly infiltrate Karnia disguised as robot soldiers to carry out the impossible assignment.
