(W) Jeff Lemire (A) Eric Koda & Various. Extraordinary X-Men versus Uncanny Inhumans! The X-Men have learned that the Terrigen Mist the source of the Inhumans' powers* but lethal to mutants has reached an irreversible saturation point. Earth is on the verge of being rendered uninhabitable to mutantkind. And now the X-Men see no other option than to strike against the Inhumans to ensure their own survival. But one X-Man doesn't take the decision lightly. Storm has literally led her teammates through hell and back* but will she command them in battle against their longtime friends and allies? What will war mean for Forge* Old Man Logan* Magik and Jean Grey? And if the X-Men come out the other side* what will be the cost? One Extraordinary era ends as another begins! Collecting EXTRAORDINARY X-MEN #17-20 and X-MEN PRIME. Rated T+