In 1983, ancient mutant En Sabah Nur, known as Apocalypse, awakens in Cairo after millennia in stasis. Disillusioned with a modern world that has strayed from divine mutant worship, he resolves to cleanse humanity and reshape the Earth in his image. Believing only the strong should survive, Apocalypse recruits four desperate mutants to serve as his Four Horsemen: the street thief Storm, the disillusioned angel Warren Worthington III, the troubled mutant-cage fighter Psylocke, and a broken Erik Lehnsherr, who has lost his secret family in Poland.Meanwhile, at Charles Xavier’s school, mutants are learning to control their powers in relative peace. However, telepathic detection of worldwide disturbances brings Raven Darkhölme back to the mansion, where she investigates the underground mutant fighting rings and rescues Kurt Wagner, a blue-skinned teleporter known as Nightcrawler. Concurrently, CIA agent Moira MacTaggert discovers strange global phenomena linked to the awakening of Apocalypse, leading her to Xavier and Hank McCoy.Apocalypse uses his immense telekinetic and molecular-manipulation powers to infiltrate the global nuclear arsenal, launching the world's warheads into space to disarm humanity, and kidnaps Xavier to absorb his powerful telepathic abilities and conquer every mind on Earth. Xavier manages to send a psychic
distress signal before his capture, which is intercepted by a young Jean Grey, Scott Summers, and Nightcrawler. They rush to the mansion just as a military strike team, led by Colonel William Stryker, captures the school's strongest students, including Mystique, Beast, Quicksilver, and Havok.The remaining young mutants stow away on Stryker’s aircraft, tracking him to a secret alkali lake facility. There, Peter Maximoff reveals a long-hidden truth: Magneto is his father. After freeing their captive friends with the help of a newly awakened, rage-fueled Jean Grey—who unwittingly unleashes the
cosmic entity within her—the team boards a stolen jet and flies to Cairo to confront Apocalypse, who has already begun tearing the city apart to build his towering pyramid.In Egypt, a titanic battle erupts. The Horsemen clash with the X-Men while Apocalypse attempts the dangerous mental transfer into Xavier's body. During the chaos, Mystique appeals to Erik’s lingering humanity, and Nightcrawler successfully rescues Xavier from the ritual chamber. Realizing Apocalypse's hypocrisy, the Horsemen turn against him. To defeat the virtually immortal tyrant, Xavier enters the astral plane to fight him mentally, while Jean Grey taps into her terrifying, unrestricted Phoenix powers, disintegrating Apocalypse down to his atoms. In the aftermath, the mutants work together to rebuild the ruined mansion, and Erik and Raven depart to forge their own paths.