Fighting for the future of mutantkind, the X-Men are locked in a battle with Bastion. When Magik is gravely injured in battle, she instinctively flees to the sanctuary of Limbo - only to fall into the clutches of a long-time adversary hoping to wrest the powerful Soulsword - and control of Limbo - from her grasp. Now a small team of X-Men venture in after her, but they are met only by unexpected peril.