Synopsis
First steps
Magneto takes his Brotherhood on the Golden Gate Bridge before moving it and use it as a transportation for the mutants, connecting it to Alcatraz Island, allowing the Brotherhood to attack Worthington Labs, in order to kill the source of the serum, and their creators. The whole complex was protected by U.S. soldiers.
Magneto made his troops charge but keep with him the strongest one, as The Juggernaut, Pyro or The Omegas. The firsts waves were decimated by the militarized serum, and Erik was unable to remove those, being fired by plastic gun instead of metal ones. While he was showing no regrets, the Omegas seems very uncomfortable looking at their leader's strategy.
As Arclight used her shock-waves to disabled the soldiers' weapons, the Brotherhood was free to run into the place, but where stopped by the arrival of the X-Men who stands between the terrorists and the soldiers and led them.
Battle inside and outside
The Omegas infiltrate the building, killing Dr. Rao, and pushing Dr. Worthington off the highest balcony. Worthington is saved by his son.
In the same time, The Juggernaut break the X-Men and US soldiers containment and ran into the complex, looking for the source of the Serum, Jimmy. Shadowcat goes on his pursuit, saving the child and defeating Cain by a smart move and using Jimmy's powers.
When Pyro and Magneto finally takes part in the battle, bombarding the complex and the field with burning cars, Iceman goes on his old , while the rest of the X-Men attacked and depowered Magneto with a Serum sample, creating first a diversion with Colossus proceeding a Fastball special with Wolverine.
Dark Phoenix Rises
When the National Guard shows-up, they instinctively begun to fire at Jean Grey who turned into the Dark Phoenix, and she begins to destroy everything and everyone there. Numerous soldiers, Brotherhood members and the entire Omega Clan were destroyed this way.
Wolverine was able approach her without dying, with the help of his regenerative healing factor. He then stabbed her, after she pledge him to save from her madness.
Aftermaths
After Alcatraz events, the United States Government proceed a mutant-friendly politics, naming Hank McCoy, Aka Beast as the US representative at the United Nations, to represent both humans and mutants American citizens.
The depowered Magneto was able to escape during the Phoenix Rise, along with many Brotherhood members. He was later seen free in a San Francisco park, recovering slowly of his magnetic powers.
The X-Men disbands shortly after the M-Day, but the Xavier's School for Gifted Youngsters reopened, welcoming numerous mutants children, including Jimmy.