Mutantkind's final war starts here. If you don't know which side you're on, check your DNA.
This story is told with a series of flashbacks. The whole issue was written by Mike Carey, with each flashback drawn by different artists:
- Events In Fortress X: Art by Mirco Pierfederici
- Basilisk: Art by Gabriel Hernandez Walta
- Cannonball & Husk: Pencilled by Carlo Barberi, Inked by Walden Wong, and Colored by Antonio Fabela
- Wolverine: Pencilled & Inked by Paco Diaz, and Colored by Matt Milla
- Magneto: Pencilled & Inked by Paul Davidson, and Colored by Brian Reber
Events of this story are completely removed from mainstream Earth-616 continuity. The characters have no memories of their previous alternate lives. As the Age of X is set in an alternate universe, many familiar characters have different names. Keeping with the continuity of the story, all characters will be referred to by their new names. The most notable changes in this issue are:
- Basilisk = Cyclops;
- Berserker = Warpath
- Nightmare = Pixie
Gambit, Trance, Rockslide, Frenzy & Cannonball patrolled Fortress X, watching for attacking Exonims & reporting any actives to Magneto. Other mutants remained within the walls of the Fortress, huddled together around a fire reliving stories of survival. Storm snuggled up to Namor to comfort him in exchange for giving up the freedom of the seas to be with her. Nightmare accidentally upset Basilisk by reminding him of his time in Alcatraz. Beserker explained why.
The island prison of Alcatraz was used for the incarceration of mutants. The Governor of Alcatraz was Arcade, who took delight in introducing Death Row inmates to their executioner. Basilisk was held completely bound on a gurney. With the flick of a switch, his mask split down the centre. He'd already had his eyelids surgically removed, so he could not contain his blasts & therefore instantly killed the mutants in front of him. As the guards wheeled him back to his cell, he managed to reach the control switch. Willingly opening his mask, Basilisk killed the guards, destroyed his chains, and went after Arcade. After executing as many human guards who tried to stand in his way, Basilisk led Callisto & the liberated mutants out of Alcatraz.
Jubilee thought all the blame should be laid on the Phoenix. She thought the destruction of Albany led the humans to such extreme actions against the mutants. Cannonball arrived and pointed out that mutant families had been hunted long before then. He recounted how he & Husk liberated three trucks of mutants from human guards. However, their true goal was to find their own family. Unfortunately, a trigger happy guard accidentally caused a massacre when the Guthrie Family was arrested. Husk was outrages at the murder of her family and the disrespect shown to their corpses which were lying in the back of a garbage truck. She moved to murder all the remaining guards, but Cannonball convinced her that there wasn't time for vengeance. They began to help the liberated mutants escape before the Exonims arrived. Yet Husk swore she would not return to flesh & blood until her brother cried for his crimes against their family's honour that day.
Meanwhile, Dazzler watched over Dr Kavita Rao as she prepared her medical equipment. Dazzler suggested moving it further away from the outer walls, but Dr Rao was more fascinated as to why everyone told stories before a battle. They did it to help remind themselves why they were fighting. However, when asked why an ordinary human was living among the mutants, Dr Rao began to tell her own story.
She had been researching scientific methods to suppress the X-Gene. However, she was also feeding information to the mutants since she disagreed with the Fordyce Clinic's ideas of feeding the cure into the water system. Information that brought Wolverine crashing into the clinic, killing anyone who stood in his way. Caught in a forcefield enforced room, he demanded to know how to destroy the cure. Since any regular methods of disposal would still leave trace elements that could be replicated, Dr Rao convinced Wolverine that his healing factor would fight & dispose of the cure without leaving any remains. Richard Palance tried to stop her from injecting the last sample but instead she injected it into Palance killing him instantly. However, the cure removed Wolverine's healing factor which left him susceptible to the poisonous Adamantium in his body. Weakened, he asked Dr Rao to finish him off. She initially refused. As the guards arrived & threatened to shoot him, Dr Rao stood in their way. She explained to Dazzler that she didn't know whether what she did saved Wolverine or destroyed him.
The mutants around the fire discussed ideals of trust & family. Mortimer Toynbee recalled the day Magneto created Fortress X. The humans believed he was dead. Colonel Graydon Creed led his soldiers who had the Chrysler Building under siege. Inside, Dust worried that she had accidentally lead them there. Cecilia Reyes tried to stop Toynbee from scaring the younger mutants with his defeatist talk, while Forge tried to keep things rational. Unknown to everyone, Mystique had already assumed the identity of a solider, and assisted a heavily wounded Magneto to the steps of the Chrysler building. The humans already believed he was dead, so they quickly had to stop using their metal ammunition against him. While Martinique & Regan Wyngarde surprised the mutants inside by suddenly turning visible, Magneto began to lift the Chrysler Building into the air. Colonel Creed's forces were unable to stop it and dozens of other metal-reinforced buildings from flying through the air. Those buildings became the founding stones with which Magneto would construct Fortress X.
A fiery X appeared in the sky. Cannonball interrupted the reminiscing to lead the mutants into battle against the human Exonims.
The events of this are immediately followed in X-Men: Legacy #245.