Collects All-New X-Men #18-21, X-Men: Gold.The X-Men are shaken to the core by the fallout from BATTLE OF THE ATOM! Kitty Pryde is particularly affected, and her faith in Wolverine's Jean Grey School is eroded. With her students gone, what is Kitty to do? Meanwhile, X-23 is back, joining the All-New X-Men and...kissing Cyclops?! What does this mean to Jean Grey? When Jean and X-23 are forced to team up against a mysterious force, she'd better figure it out fast! Plus: it's the 50th Anniversary of the X-Men, ring it in with some of the greatest creators to ever work on the X-Men!