Christopher Reeve not only dons the hero's cape for the fourth time in Superman IV but olso helped develop the film's provocative theme: nuclear disarmament. To make the world safe for nuclear arms merchants, archvillain Lex Luthor creates a new being to challenge the Man of Steel: the radiation-charged Nuclear Man. The two foes clash in an explosive extravaganza that sees Superman save the Statue of Liberty, plug a volcanic eruption of Mount Etna and rebuild the demolished Great Wall of China.