Plutonium Man was created by Will Magnus shortly after he came out his coma. Magnus was kidnapped by an organization that brainwashed him. While the Metal Men went to rescue him, Magnus' sanity had disappeared as he constructed the most dangerous foe of the Metal Men yet. The loyal robots sacrifice themselves in battle to defeat the newly created menace. Magnus was unable to forgive himself and tried to recreate them, but was unable to do so because his mind was fractured and had not fully healed.