The X-Men and their allies face war on every front! X-Factor comes up against their deadliest challenge yet in Apocalypse and his Horsemen, including the all-new – and all-too-familiar – Archangel! The New Mutants lose one of their own on an island of horrors! The X-Men take on the lethal Marauders – and the survivors will be asked to sacrifice themselves to stop the demonic Adversary! Featuring tie-ins starring Captain America, Daredevil, the Fantastic Four, the Hulk and Power Pack, this is one of the most devastating X-Men crossovers of all time!