Watch X2: X-Men United

The fate of mutantkind is at risk after a mutant, a person with superhuman abilities, attacks the United States president. Xavier, a telepath and head of a school for mutants, decides to find out who planned the attack in order to protect the already tenuous relations between humans and mutants. He takes one of his X-Men team, a group of mutants trained to combat super-powered threats, with him to visit his imprisoned nemesis Magneto. Magneto reveals that it is a mutant-hating government agent named Stryker behind the attack. Magneto turns out to be bait and Xavier is caught in a trap set by Stryker. With Xavier's school now seemingly unprotected, Stryker sends in a force to raid the it under the pretense of collecting dangerous mutants. Many of the students are captured but the mutant Wolverine escapes with others. Meanwhile two other X-Men Jean Grey and Storm track down the mutant responsible for the assassination attempt and find out that he was mind-controlled by Stryker into making the attack. Magneto escapes his imprisonment and allies with the X-Men to stop Stryker. They trace Stryker to a remote military base with all of its operations hidden underground beneath a huge dam. Using his own mutant son's mind-control powers on Xavier, Stryker intends to use Xavier's telepathic abilities to destroy all of the world's mutants. While the others go to find Xavier and rescue the hostage children, Magneto tries to fulfill his own evil plan to make Xavier kill all the humans, instead. The X-Men stop Magneto and he is forced to flee as the dam breaks. The ensuing flood kills Stryker. As the X-Men try to escape their jet stalls and Jean uses her powers to protect them from the flood then dies in the deluge once the plane is in the air. They fly to Washington and provide the president with proof of Stryker's plot to destroy the mutants, exonerating mutants of any wrong doing.