After the events of the first film, Logan has left the X-Men to hunt down his half-brother, Sabretooth (real name Victor Creed), who has teamed up with the villainous Magneto (real name Erik Lensherr) and the Brotherhood of Mutants. In a bar, he encounters Yuriko Oyama, an old flame, and they leave together. Shadowcat is able to send a distress signal to the X-Mansion, so Xavier sends Cyclops and Jean to join them and stop Essex, who prepares to unleash his own army mutants with which he plans to conquer the world. Unknown to the group, Essex himself has begun to mutate.