Rachel Summers claims the power of Phoenix, Jean Grey returns from a watery grave and the original X-Men reunite as X-Factor! It's an era of upheaval that puts Marvel's mutants on the path to some of their darkest days! Both Cyclops and Professor X leave the X-Men, but a new teammate waits in the wings: Magneto?! As Storm steps up and Wolverine faces the new Phoenix, the relentless Nimrod targets the team for annihilation! Meanwhile, the newly minted X-Factor grapples with Jean's miraculous resurrection and shares a fateful first encounter with Apocalypse! Plus: The X-Men and New Mutants enlist in the Asgardian Wars, Nightcrawler goes solo and Longshot debuts! Collecting Uncanny X-Men (1981) #194-209; X-Men Annual (1970) #9-10; New Mutants Special Edition #1; New Mutants Annual #2; Nightcrawler (1985) #1-4; Longshot #1-6; Avengers (1963) #263; Fantastic Four (1961) #286; X-Factor (1986) #1-8 and Annual #1; Iron Man Annual #8; Amazing Spider-Man (1963) #282; and material from Marvel Fanfare (1982) #33, and Classic X-Men #8 and #43