X-Men, still grieving over the death of Phoenix (Jean Grey), are investigating a case of a missing mutant girl in Northern Japan. This leads them to a mysterious virus that turns mutants into monsters. U-Men and the Inner Circle want it.

The X-Men are reunited following the death of a teammate, and are summoned by Charles Xavier to Japan following the abduction of Hisako Ichiki (Armor). There, they confront the U-Men, a lunatic cult that steals and transplants mutant organs to further strengthen their own army, and the battle for justice is on.—Ismail Shihadeh