When a cure is found to treat mutations, lines are drawn amongst the X-Men—led by Professor Charles Xavier—and the Brotherhood, a band of powerful mutants organised under Xavier's former ally, Magneto.

After the re-emergence of the world's first mutant, world-destroyer Apocalypse, the X-Men must unite to defeat his extinction level plan.

The ultimate X-Men ensemble fights a war for the survival of the species across two time periods as they join forces with their younger selves in an epic battle that must change the past – to save our future.