Unbreakable X-Men #2

ATLANTIS UNDER SEIGE! X YEARS LATER, a grief-stricken GAMBIT has a mission to recover and recall several unwilling X-MEN who have left the mutant life, to face a creature of nightmares that can doom them all! It's the return of several beloved mutants (and a few less beloved), coming back to try to contain the unimaginable army of the undead that threatens both Atlantis and the surface world!