Full story
In 1845, in Canada, young James Howlett watches groundskeeper Thomas Logan kill his father. Bones burst from his hands as claws and he kills the man, who reveals with his last breath that he's James's real father. James runs away with Victor Creed, his half-brother, who also has a healing factor and a beast's instincts. The two fight side by side through more than a century of wars: the American Civil War, both World Wars and Vietnam.
In Vietnam, Victor goes too far and both of them face a firing squad, which does nothing. Major William Stryker recruits them into Team X, a mutant squad with Agent Zero, Wade Wilson, John Wraith, Fred Dukes and Chris Bradley. On a mission in Nigeria, the group slaughters a village while hunting for a meteorite, and Logan walks away. Six years later he works as a lumberjack in Canada and lives with schoolteacher Kayla Silverfox.
Stryker resurfaces saying someone is killing off the old team. Soon after, Logan finds Kayla dead and blames Victor. The brothers fight and Logan loses. To get strong enough for revenge, he signs up for the Weapon X program: his skeleton is bonded with adamantium, an unbreakable metal. Before they can wipe his memory, Logan escapes, hides on a farm and watches Zero kill the old couple who took him in. Logan kills Zero and looks for answers with Wraith, Dukes and the thief Remy LeBeau, Gambit.
The truth comes out on Three Mile Island, where Stryker keeps mutants locked up. Kayla is alive. She faked her death because Stryker was holding her sister. Victor was played too and never got the adamantium he was promised. Stryker has combined the powers of his captives in Wade Wilson, now Weapon XI, with blades in his arms and his mouth sewn shut. Kayla and Logan free the young prisoners, Scott Summers among them, and Professor Xavier shows up to take them in.
Logan and Victor team up against Weapon XI on top of a cooling tower. Logan cuts off his head and the tower collapses. Victor slips away, and Gambit helps Logan get out. Stryker shoots adamantium bullets into Logan's head, and he survives but loses his entire memory. Kayla dies of her wounds, and Logan leaves without remembering who she was. In the post-credits scenes, Stryker is arrested for a general's death, Logan drinks at a bar in Japan and Weapon XI's hand moves in the rubble.