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.

In the 1960s, superpowered humans Charles Xavier and Erik Lensherr work together to find others like them, but Erik's vengeful pursuit of an ambitious mutant who ruined his life causes a schism to divide them.

The X-Men send Wolverine to the past in a desperate effort to change history and prevent an event that results in doom for both humans and mutants.

In the 1980s, the X-Men must defeat an ancient all-powerful mutant, En Sabah Nur, who intends to thrive by bringing destruction to the world.

When anti-mutant Colonel William Stryker kidnaps Professor X and attacks his school, the X-Men must ally with their archenemy Magneto to stop him.

In a world where mutants (evolved super-powered humans) exist and are discriminated against, two groups form for an inevitable clash: the supremacist Brotherhood, and the pacifist X-Men.

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.