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.
Almost one long and peaceful decade after the nearly disastrous events in X-Men: Apocalypse (2016), Professor Charles Xavier's X-Men enjoy a mutually beneficial pact with the humans, undertaking increasingly dangerous missions as the Earth's valiant protectors. However, during a risky NASA crisis in 1992, Jean Grey is imbued with an unfathomable cosmic force--and even though she should be dead--this inexhaustible but uncontrollable energy enhances her already formidable abilities, transforming her into an all-powerful being. More and more, Jean's otherworldly powers become unpredictable and destructive, posing a direct threat not only to herself and her companions but also to the entire world. Is humankind prepared for the rise of the Dark Phoenix?