Uncanny X-Men #244 VF+
Marvel 25th Anniversary Cover!
This issue continues one of the darkest chapters in mutant history. A mercenary force called the Marauders attempts to commit genocide on the outcast Morlocks, and the only thing standing in their way is the X-Men and X-Factor. This is a storyline that has repercussions on the X-titles for years to come. When the X-Men finally catch up to the murderous villains one of the costliest battles in X-Men history follows. It's a battle that will leave several members of the team severely injured. Story continues in New Mutants #46 and Power Pack #27.
NOTE: Includes the Mutant Massacre Map, a key to following the events in this pivotal storyline