The Ultimates are a cadre of Super Heroes employed by the U.S. government to face threats to humanity too powerful for conventional operatives to handle. Led by General Nick Fury, the roster includes billionaire playboy Tony Stark, better known as Iron Man; Captain America, a World War II super-soldier whom fate has thrust into the twenty-first century; an environmental activist who claims to be the Norse god Thor; and Janet Pym, a scientist whose mutant powers allow her to shrink to the size of a wasp.