The X-Men have just averted the Age of Apocalypse, but the threat of Onslaught looms right around the corner - a villain so powerful he put the unstoppable Juggernaut into a coma! But before the X-Men can learn more about this shadowy foe, they must face Gene Nation, led by the vicious Marrow - and help Magneto's Acolytes battle Apocalypse's son, Holocaust, who escaped the AoA into the Marvel Universe! Plus: How will the world react when the Legacy virus' existence is made public? Can Rogue handle learning Gambit's greatest secret? And did Sabretooth's brain damage truly change his personality, or is he a time bomb waiting to go off? All this, and the Xavier Institute enrolls a new student!