The film opens with a brutal Action Movie sequence: the mutant Nightcrawler, under mind control, launches a terrifying assault on the U.S. President in the White House. This public display of mutant aggression fuels anti-mutant hysteria led by the military leader William Stryker.

Wolverine (Logan) returns to the X-Mansion seeking answers about his past, only for Stryker’s black-ops forces to launch a devastating overnight raid, successfully capturing several students and Professor Charles Xavier. In a frantic escape sequence, Jean Grey, Cyclops, Rogue, and Iceman flee, while Logan engages in a savage fight for survival before making his own brutal getaway.

The remaining X-Men realize their only chance lies in a dangerous and improbable alliance with their nemesis, Magneto (Erik Lehnsherr), who also knows of Stryker's sinister operation at Alkali Lake. This desperate team-up is facilitated by Mystique, who begins a critical infiltration mission to uncover Stryker’s true motive.

The combined mutant forces launch an intense assault on Stryker’s hidden military base. Their primary mission is to rescue the captive children and, more crucially, prevent Stryker from using a replicated Cerebro machine, amplified by his son Jason’s powers, to execute a horrifying genocide. The thrilling climax features Logan confronting Stryker and finally facing fragmented, agonizing memories of his past in the notorious Weapon X program.

In a heart-pounding race against time, Magneto and Mystique betray the X-Men, hijacking the amplified Cerebro to reverse its targeting, intending to kill all humans. The heroes must battle Magneto’s catastrophic plan while simultaneously escaping the collapsing base. The film culminates in a powerful, emotional sacrifice: Jean Grey unleashes the terrifying potential of the Phoenix Force to save her friends, tragically disappearing beneath the icy waters of Alkali Lake.