Computer programmer Gus Gorman (Richard Pryor) is hired by financial tycoon Ross Webster (Robert Vaughn) to seize control of a weather satellite and annihilate Colombia's coffee crop. When Superman (Christopher Reeve) manages to thwart the plan, Webster commands Gorman to use the satellite to locate kryptonite, the Man of Steel's mortal weakness. But a missing unknown element in the kryptonite -- replaced by Gorman with tar -- causes an unintended side effect when presented to Superman.