Professor Xavier warns the X-Men about an impeding event that wipes half the mutant population: Nitro will self-detonate in Genosha. The Brotherhood rescue Nitro from a government prison against his will and use Psylocke to control him, planning to use him as a weapon. The X-Men chase the Brotherhood in order to prevent Genosha's destruction.

Wolverine and Mystique fight Maverick and Sabretooth to protect Maverick's daughter Christie. Wolverine discovers some pieces of his past at Weapon X.

When the M.R.D. creates mutant hunting Sentinels, the X-Men and the Brotherhood team up to take down them, and Master Mold, down.

In the future, Marrow has developed a strong friendship with the re-programmed sentinel.

Jean Grey a été enlevé, mais alors que les X-Men commencent la recherche, un nouveau problème se pose. Magneto a forcé la main du sénateur Kelly à lancer une attaque sentinelle sur Genosha afin qu'il puisse riposter et commencer la guerre! Pendant ce temps, dans le futur, Mastermold a capturé Xavier et le force à révéler les emplacements des mutants partout dans le monde!