This entry in the retro X-Men series finds the mutants in the series-alternate universe year of 1983, ten years after the events of Days of Future Past, where the cold war is rampant between the United States and the Soviet Union, with most people already worried about being on the brink of annihilation of life on Earth within just a few hours if nuclear war should ever break out. Erik Lehnsherr, aka Magneto, is living as a closeted mutant to keep his family safe, working as a metal worker in Poland with a loving wife and daughter. Professor Charles Xavier is at the mansion that serves as the School for Gifted Youngsters (aka, mutants confronting who they are and learning to control their powers). Both have their home worlds rocked in tragedy. And Mystique spends her time traveling to the four corners of the Earth in order to liberate mutants wherever she can, such as the German teleporter, Nightcrawler. The mutants begin to fight amongst each other yet again when the world's first mutant, the powers-absorbing En Sabah Nur, aka Apocalypse, is resurrected from his dormant state since 3600 B.C., wastes no time in hatching a plan to lay conquest to the entire planet. He sets about pulling together powerful mutant accomplices, dubbed his Four Horsemen, in an effort to bring humanity under their rule, after threatening them with nuclear annihilation. Now it's up to Xavier, Mystique, Beast, and a band of untested gifted students to fight for the right of people who want their kind destroyed from being crushed under the rule of these mad mutants.