Following the death of Jean Grey (who was being controlled by the Dark Phoenix, due to the sinister influence of the Inner Circle), the X-Men are reassembled by Professor X to travel to Japan following the abduction of Armor and face the U-Men who are abducting young mutants in order to harvest their organs. During their fight with the U-Men, the X-Men discover that some of the mutants in Japan are suffering from the "Damon Hall Syndrome" which causes problems for mutants during their second mutation. The X-Men must also deal with the next plot of the Inner Circle.