X-Men First Class: Before Charles Xavier and Erik Lensherr took the names Professor X and Magneto, they were two young men discovering their powers for the first time. Before they were archenemies, they were closest of friends, working together, with other Mutants (some familiar, some new), to stop the greatest threat the world has ever known. In the process, a rift between them opened, which began the eternal war between Magneto's Brotherhood and Professor X's X-MEN.
X-Men: In an era of growing hostility toward super-powerful mutants, misguided Magneto's scheme for transforming the world's leaders into brother-mutants relies on sacrificing alienated Rogue. But Magneto has underestimated altruist Xavier's X-Men and their enigmatic ally Logan.
X2: After an anti-mutant "black ops" specialist abducts Xavier, imprisons his students and steals Cerebro, the fugitive X-Men and newcomer Night Crawler join forces with Magneto to rescue their brethren and forestall a holocaust.
X-Men: The Last Stand: Killing Xavier and liberating evil mutants, Magneto uses the resurrected Jean Grey -- now Phoenix, the most powerful mutant of all -- against the X-Men. While Logan recruits members of Xavier's original team and confronts an emerging relationship with Storm, Rogue and Iceman come into their own as the X-Men's future.