The mutant detective agency X-Factor specializes in superhuman cases. But nothing has prepared them for their newest client: the Norse goddess Hela. Tricked into helping her recapture an escaped slave, the team decides they must travel to Las Vegas and confront the queen of the underworld to free her unwilling jester. But Norse divinity does not take kindly to the challenges of mere mortals - even mutant ones - and the members of X-Factor soon find themselves surrounded by undead Viking warriors in the streets of Sin City. Their only hope: a certain hammer-wielding God of Thunder!The series has been collected in the following paperbacks:X-Factor: The Longest Night - (#1-6)X-Factor: Life And Death Matters - (#7-12)X-Factor: Many Lives Of Madrox - (#13-17)X-Factor: Heart Of Ice - (#18-24)Messiah Complex - (#25-27)X-Factor: The Only Game In Town - (#28-32)X-Factor: Secret Invasion - (#33-38)X-Factor: Time And A Half - (#39-45)X-Factor: Overtime - (#46-50)X-Factor: Invisible Woman Has Vanished - (#200-203)X-Factor: Second Coming - (#204-206)X-Factor: Happenings In Vegas - (#207-212)X-Factor: Scar Tissue - (#213-219)X-Factor: Hard Labor - (#220-224)Super Unnatural (#224.1, #225-228)They Keep Killing Madrox (#229-232)