During a rescue mission in space, Jean-Grey nearly dies when she gets hit by a mysterious cosmic force. Upon her return, the force has made her not only more powerful but also far more unstable. The X-Men now find themselves facing one of their own as their most formidable and powerful foe, as Jean begins to spiral out of control, hurting her loves ones and unravelling the very fabric that holds the team together. They have to find a way to unite and save Jean's soul as well as Earth from aliens who want to rule the galaxy by weaponising the force.