The extra-length finale of this best-selling shocker! All the secrets are revealed -- Who is the third Summers brother and what happened to him? What really happened on Krakoa all those long years ago? And why has Xavier been keeping it to himself for so long? All this, and the all-out battle between the X-Men and their newest, deadliest foe, and a conclusion that will set-up events that rock the X-universe for years to come—starting when Ed Brubaker jumps to UNCANNY X-MEN this July!
— Description from Comic Vine community (comicvine.gamespot.com).
