While the X-Men and Brotherhood are at a survival training camp, Mystique releases the unstoppable Juggernaut. But when the unstoppable mutant threatens both teams, the X-Men and Brotherhood must work together in order to stop him.
While the X-Men and Brotherhood are at a summer camp learning survival training, Mystique releases Cain Marko, the unstoppable Juggernaut, in hopes of getting his help in obtaining Xavier's mutant location system, Cerebro. But when the unstoppable mutant threatens both Charles and Mystique, the X-Men and Brotherhood must learn to cooperate and work together in order to stop him.