"No more mutants." With those fateful words, the Scarlet Witch ushered in one of the most shocking eras of all for mutantkind - with fan-favorite characters depowered and only 198 mutants believed left on Earth! Even worse, they're not being born - and those who remain must grapple even more than ever before with the threat of extinction! How do the X-Men pick up the pieces in a world that has completely changed? Can a traumatized Quicksilver cope with losing his super-speed? What comes next for the ever-unpredictable X-Factor? What is the Sentinel Squad? And out of the ashes of Decimation, a deadly new force emerges that proves to be bad news for Alpha Flight and the New Avengers! Collecting HOUSE OF M (2005) #8, MUTOPIA X #5, DECIMATION: HOUSE OF M - THE DAY AFTER, X-MEN (1991) #177-179, NEW X-MEN (2004) #20-24, X-FACTOR (2005) #1-4, GENERATION M #1-5, SON OF M #1-6, X-MEN: THE 198 #1-5, SENTINEL SQUAD O*N*E #1-5, NEW AVENGERS (2004) #16-20, X-MEN UNLIMITED (2004) #13 and X-MEN: THE 198 FILES.