Several mutants gather on Muir Island, looking for a cure for their uncontrollable powers. The appearance of seemingly cured Warren Worthington is all that they need to accept Adler's offer to cure them. Cyclops claims that their powers are a gift, not a disease, but the mutants don't listen. Xavier and the X-Men return to Westchester. Meanwhile, Mystique and Apocalypse transform four mutants into Horsemen of Apocalypse. They attack the world peace summit in Paris. The X-Men see the attack on TV, and Xavier is worried by the threat of Apocalypse. He also recognizes the four Horsemen as the mutants treated by Adler, and sends Rogue back to Muir Island to find out the truth about Adler and his work.
— Description from Comic Vine community (comicvine.gamespot.com).
