The second year of Mark Millar’s groundbreaking ULTIMATE X-MEN! As the X-Men embark on their inaugural world tour, they must confront some unsettling truths about their mentor, Professor Charles Xavier. Before founding his school for young mutants, Xavier abandoned his only son, David, a mutant with uncontrollable reality-warping abilities. Now David has returned, looking to exact revenge on the father who left him – and he’s willing to eradicate anyone who stands in his way! Will the X-Men be forced to kill Xavier’s son to end his threat against the world? In the wake of tragedy, their suspicions of their leader’s methods only increase. Xavier’s mental blocks on student Jean Grey’s psychic abilities continue to crumble, and she grows increasingly unstable – plagued by visions of a world engulfed in the flames of a fiery phoenix! Plus: Meet the mutant street hustler known as Gambit! Collecting: Ultimate X-Men (2001) #13-25