This hardcover volume features many key introductions, including Proteus (the evil son of Professor X), Gambit (who enjoyed a large fan-following in the hit X-Men cartoon) and Phoenix (the dark split personality of Jean Grey). The X-Men are cut to the emotional core as they battle their way through an obstacle course of deadly trials. First, Professor Xavier -- the mentor of the X-Men -- is forced to confront his past sins when his own son explodes into a destructive force. The question is, will he sacrifice his team to save his son? Then, the X-Men face another internal conflict when Jean Grey turns to the dark side. To save themselves, and the world, will the X-Men strike down their own teammate?