The X-Men face their most formidable and powerful foe when one of their own, Jean Grey, starts to spiral out of control. During a rescue mission in outer space, Jean is nearly killed when she's hit by a mysterious cosmic force. Once she returns home, this force not only makes her infinitely more powerful, but far more unstable. The X-Men must now band together to save her soul and battle aliens that want to use Grey's new abilities to rule the galaxy.

Professor Charles Xavier and his team of genetically gifted superheroes face a rising tide of anti-mutant sentiment led by Col. William Stryker. Storm, Wolverine and Jean Grey must join their usual nemeses—Magneto and Mystique—to unhinge Stryker's scheme to exterminate all mutants.