The threat of the mutant menace has reached a point where ordinary citizens must take of the fight on which the governments of the world have been lax! An evolutionary biologist and a dentist travel to South America and uncover a city population unlike any the world has seen … and unleash its deadly force on an unsuspecting mutant population. All in a day's work for the X-Men, right?

Dead Wrong.

In the critically-acclaimed debut of writer Grant Morrison (The Invisibles) and penciler Frank Quietly (The Authority), the X-Men will face an opponent unlike any before, and be forced to make some of the most difficult decisions they've ever faced.

Can even some of the most powerful beings on the planet withstand the coming storm?