When Jean Grey returns from a watery grave, the original X-Men reunite - as X-Factor! But for Marvel Girl, Cyclops, Beast, Angel and Iceman, posing as a mutant-hunting organization gets complicated fast! And things get worse when the ageless villain Apocalypse makes the scene! Then, when X-Factor is drawn into the chaos of the Mutant Massacre, Angel suffers a grievous injury and will be changed forever! As X-Factor rescues young mutants - including Leech, Boom-Boom and Rictor - the Beast undergoes a radical metamorphosis, Iceman battles alongside Thor, tragedy pushes Cyclops to the brink of insanity and a traitor stalks the team from within! Will Apocalypse's Four Horsemen put the final nail in X-Factor's coffin? Collecting AVENGERS (1963) #263, FANTASTIC FOUR (1961) #286, X-FACTOR (1986) #1-26 and ANNUAL #1-2, IRON MAN ANNUAL #8, AMAZING SPIDER-MAN (1963) #282, THOR (1966) #373-374 and #377-378, POWER PACK (1984) #27 and #35, MEPHISTO VS. #2, INCREDIBLE HULK (1968) #336-337, SECRET WARS II #5, and material from MARVEL FANFARE (1982) #40 and CLASSIC X-MEN #8 and #43.