The Beast greets the heroes warmly, which is strange to the human-form Beast that has been adventuring with the X-Men. The Beast explains that he is from an alternate reality that was ruled by Apocalypse. He was thrown into this reality's past 20 years ago when his reality ceased to exist. He offers the X-Men a device capable of tracking Apocalypse in exchange for access to their scientific equipment.
The heroes, with this new Beast in tow, return to the X-Mansion to rest and heal. They hear the news that Avengers mansion was destroyed by the Masters of Evil and the Avengers have been badly hurt. Magneto calls from Muir Island and reminds them of the urgency of their mission - find the missing teammates!
Suddenly the Apocalypse detection device goes crazy... Apocalypse just appeared in Washington DC with his "four horsemen" and demanded the surrender of the President! The X-Men leap into action! When they arrive on the scene, they witness the destruction that has been wrought. They also notice Uatu, the Watcher, a cosmic level being who appears to record historically significant moments in time. The X-Men attack, only to realize that the four horsemen are their four missing teammates - Magma, Rogue, Angel, and Sunspot, all of whom are now controlled by Apocalypse!
In the combat, Longshot quickly goes down as does the Beast. Wolverine takes down Sunspot but makes a tactical error in attacking Apocalypse directly! It appears the X-Men will be easily defeated when a man with grey hair wearing body armor appears above the battle... Cable! He is badly injured and passes along this message, "The Scarlet Witch! She is the end of all mutants! No more mutants! You must stop her! She's too powerful to live!" Images of the horrible future (Avengers Disassembled, House of M, Decimation, Schism, Mutant Extinction) flash in the minds of all assembled - including Apocalypse. Apocalypse teleports away with his horsemen saying, "With the Scarlet Witch's power I could reshape the world in my image!"
The X-Men scramble to the New Jersey suburb where the Scarlet Witch and her husband the Vision live. The town is on flames - the Avengers are losing a pitched battle to defend the Scarlet Witch against Apocalypse (which is odd because the Avengers are still recovering from their mansion being destroyed...). Approaching, the X-Men are surprised when the Scarlet Witch blasts their plane out of the air!
The X-Men escape the burning vessel and rush into combat only to be stopped when the Scarlet Witch summons Magneto, Quicksilver, Crystal, and Wonder Man to defend her! They quickly engage in a three way battle -
On one side are the X-Men - Longshot, Colossus, Wolverine, and Beast.
On another side are Apocalypse and his three remaining horsemen - Rogue, Angel, and Magma!
On the final side are the Scarlet Witch's reality-warped puppets: Magneto, Quicksilver, Crystal, Wonder Man, Vision, and Agatha Harkness!
Apocalypse swiftly knocks Agatha Harkness down and Rogue steals Magneto's powers, putting Magneto out of commission. The Vision and Wonder Man quickly defeats Wonder Man's good friend, the Beast, and Magma puts Longshot out of commission. A battered Colossus is barely standing. Crystal and Angel exchange blows Quicksilver and Wonder Man pound on Wolverine with a flurry of blows, almost knocking him unconscious.
As a last ditch desperation grasp at victory, Wolverine goes into a berserker rage and beheads the Scarlet Witch!
Instantly, the Avengers and her extended family are returned to their rightful places. Apocalypse, his prize stolen from him, says that the Scarlet Witch must not have been strong enough to survive and disappears, leaving his failed horsemen behind. The X-Men pick up their fallen comrades and head home. A dark future was averted but at what cost?