Superman IV: The Quest for Peace

Superman IV: The Quest for Peace is the fourth and final Superman movie, and the fifth in the series overall including Supergirl. Released four years after the third installment and nine after the first, it was the only movie in the series that did not involve Ilya Salkind. Sidney J. Furie took over directing. It is widely considered the worst Superman movie ever made.

Plot
After Superman rescues cosmonauts floating in space without oxygen, he returns to Earth as Clark Kent to deal with selling his family farm after his foster mother Martha Kent's death, finding an energy module in the star ship that brought him to earth that the voice of his birth mother Lara says can only be used once. Following that, he returns to Metropolis to find that the Daily Planet has been bought out by the tabloid tycoon David Warfield, and that Perry White has been replaced as its editor by David's daughter Lacy, who starts making advances toward Clark despite Lois' warnings that Clark is "the oldest Boy Scout".

Soon the President of the United States makes a speech on television that peace talks between the United States and the Soviet Union have failed and that they are now considering building up nuclear defenses for possible war. Jeremy, an elementary school student whose class was watching this speech, is motivated to write a letter to Superman, saying if he could destroy all the world's nuclear missiles, then the world could be spared from blowing up one another. Superman initially tells Jeremy that he couldn't do that -- a response that the Warfield-controlled Daily Planet spins as SUPERMAN SAYS DROP DEAD TO KID -- but after a private talk with Lois Lane on the issue, he realizes that Earth is his home as well and he can't stand idly by and watch its citizens annihilate each other. He addresses the United Nations by stating that he will destroy all nuclear missiles starting immediately; a statement that gets surprisingly universal support.

Meanwhile, Lex Luthor breaks out of prison with the help of his nephew Lenny and comes up with a new plan to destroy Superman: by creating a superpowered being cloned straight from Superman's own DNA, a sample of which he gets from a museum display showing the strength of Superman's single hair strand. Luthor gets help from a few hired black market arms dealers to attach a device that contains what he calls a "genetic stew" onto one of the nuclear missiles which Superman will throw into the sun as he did all others. As the missile with the device reaches the sun and is destroyed, it instantly transforms the "stew" into a superhuman being with incredible power. He flies back to Earth and meets Luthor at his penthouse hideout, referring to him as Nuclear Man, the only being with the power to pierce Superman's skin and make him weak enough to die. Of course, Luthor shows his nephew that Nuclear Man needs direct sunlight to function or else he will be powerless.

One day, Lois Lane meets with Lacy Warfield at her apartment for a double date where Superman tries to entertain them as both himself and Clark Kent when he gets a secret video message from Lex Luthor, forcing Kal-El to meet at his penthouse. Superman interrupts the date to deal with Luthor, only to find himself face-to-face with his creation Nuclear Man. The two end up in a struggle that takes them all across the world, with Nuclear Man causing various disasters and Superman trying to fix them. Eventually they end up in New York where Nuclear Man threatens to dump the Statue of Liberty in the heart of the city. Superman stops that from happening and flies the statue back to Ellis Island, but Nuclear Man takes advantage of this and pierces Superman's skin with his fingernails. Weakened from contact, Superman drops to the ground after putting the statue back in place, and then Nuclear Man kicks him high into the sky, causing his cape to drop onto the torch.

Soon the Warfield press machine spins out SUPERMAN IS DEAD, and its publishers now have Superman's cape in their possession. This outrages Lois to the point where she takes the cape off their hands even amidst David Warfield firing her. She goes to Clark's apartment and finds him at home sick, something she never saw happen to him. Lois hands Clark Superman's cape and tells him she just wants Superman to know how much she loves him. After she leaves, Clark pulls out the energy module from the star ship, with the voice of his mother saying that if it can restore his powers, the sacrifice will not be in vain.

Meanwhile, Luthor rejoices at all the money his arms dealers were making from the demise of Superman and the rearming of the world, though he chooses to end their partnership and take all the profits for himself, using Nuclear Man's powers to get the point across. Luthor now feels secure in that he has a superpowered being at his disposal. However, Nuclear Man starts having desires for Lacy Warfield when he sees her picture in the papers. Superman, with his powers and health restored, senses this and tries to stop Nuclear from reaching Lacy as he threatens the citizens of Metropolis with his powers. Superman tricks Nuclear Man into entering an elevator car and then drags it out into space, dumping it on the dark side of the moon where he will remain inert and powerless due to lack of sunlight. However, a bit of the sun's light does creep into the elevator car and repowers Nuclear Man, resulting in a fight with Superman on the moon which leaves the Kryptonian overwhelmed but not depowered. He goes back to Earth, kidnaps Lacy Warfield, and drags her off into space while Superman pushes the moon in front of the sun, causing Nuclear Man to lose his powers. Superman quickly brings Lacy back to Metropolis and then deposits Nuclear Man into the heart of a nuclear reactor, where he becomes a powerful energy source.

Soon David Warfield watches as Perry White restores the Daily Planet to the respectable newspaper it used to be, saying that he secured a loan to buy out the remaining shares of the paper, reducing David to a minority shareholder and protecting it from further abuse. Jimmy Olsen and Lois Lane are glad to have their old jobs back. At a press conference Lois attends, Superman tells the people that the only way the world can have true peace is if they want it so badly that the governments will have no choice but to give it to them.

At the end of the movie, as Luthor and his nephew try to make their getaway, Superman captures them and flies off with their vehicle. He first takes Lenny to Boys Town, where the presiding pastor will watch after the young man and teach him well. He then takes Luthor back to the prison that he escaped, letting Luthor know that he knew about Nuclear Man's weaknesses and that he will see him in twenty years.