As the struggle between man and mutant continues, a "cure" for mutation is discovered, allowing those with superhuman abilities to rid themselves of their burden and fully integrate into society. The mutant community quickly finds itself a house divided over the issue, with those who choose to retain their abilities -- qualities they believe to define their very essence -- on one side, and those, like X-Men team member Rogue (Anna Paquin, Almost Famous), who long to rid themselves of a power that keeps them from enjoying a normal life on the other. Lurking in the shadows is a group of mutants that see the introduction of the cure as further proof that man and mutant cannot co-exist, despite a pro-mutant President and a mutant in the President's cabinet, Beast (Kelsey Grammer). Led by Magneto (Ian McKellen), these mutants prepare for the final confrontation between the species -- and are joined by a surprising character from the past. Meanwhile, Cyclops (James Marsden) mourns a personal loss and searches for answers while Wolverine (Hugh Jackman), Storm (Halle Berry), and Professor Xavier (Patrick Stewart) must confront the growing threat to peace and deal with the transformation of one of their own into an all-powerful being named "Phoenix."