Synopsis
This issue is split into 2 interleaved parts. One is the conclusion to the final battle begun last issue, and the other is a flashback to 3 days before the battle, but after Hope Summers beat off Cyclops in #10. I will separate the 2 strands out. There is also an epilogue.
In the flashback Iron Man summarises the situation as he sees it. At the end of House of M the insane Scarlet Witch depowered most mutants, and prevented more from arising. Tony Stark theorises that the Phoenix Force reacted to that by causing Hope to be born. It was believed that she was the Mutant Messiah, who would gain the Phoenix power and re-allow new mutants.
Iron Man is addressing an assembly of Avengers (Black Widow, Captain America, Dr Strange, Hawkeye, Iron Fist, Luke Cage, Ms Marvel, Red Hulk, Spider-Woman, Thing, Thor and Wolverine) in their refuge in the mystical city of K'un Lun. He reminds them that they have tried deflecting or containing the Phoenix Force before it reached Earth recently (the deep-space team in Avengers and Secret Avengers), but failed. He mentions that they tried to split it up (but strangely not that he himself succeeded in #5 and split it between 5 X-Men). He just says they've failed to kill it or control it.
He says that Scarlet Witch and the now K'un Lun-trained Hope are the only ones who have been able to damage the Phoenix Force. Having studied the historical account of K'un Lun's previous encounter with the Phoenix, Tony has come to the conclusion that their only course is to trust that these 2 can prevail together.
However Wanda and Hope are far from working together, because Hope blames the Witch for starting Cyclops down the path to ruling the world with the Phoenix Force. Tony and Cap find them fighting each other (with devastating side-effects).
After they've calmed down, Cap asks Hope what will happen after they defeat Phoenix-powered X-Men (now reduced to Cyclops and Emma Frost). Will Hope become the Phoenix? And will she be any better than the current holders of the power?
3 days later, and Cyclops drained the remaining Phoenix power from Emma Frost last issue, and became Dark Phoenix. He is still facing an array of Avengers (Iron Man, Ms Marvel, Red Hulk, Thor) and X-Men (Havok, Iceman and what looks like Gambit), or both (Storm) or neither (Hulk), but the scene seems to have shifted from Utopia Island to the Himalayas undergoing volcanic eruptions.
At the Jean Grey School the Stepford Cuckoos are using Cerebra to monitor what's happening worldwide, and pass the information to Captain America. Cyclops' rage is causing massive destruction all over the world, from volcanoes, tidal waves, fires, earthquakes and meteor strikes. Cap is on the way to the Himalayas in a quinjet with Beast and Iron Fist.
We see other heroes helping deal with catastrophes in various places:- Gambit and Hawkeye in Paris; Angel and Spider-Man in Beijing; Giant-Man and Pixie in the Mediterranean; Captain Britain and (probably) Rogue in the Amazon. We see Cyclops blasting Thor into space in the Himalayas. But strangely we also see him punching Hulk in Sydney so hard he lands in Sacramento.
Meanwhile Cap's group have joined the fight in the Himalayas. Wolverine's there too. But Dark Phoenix blasts them all, and flies off. Iron Man says it's time for their last shot, and Cap puts out a broadcast call for any Avenger who can bring Cyclops back. Nova responds, and smashes into the flying X-Man, bringing them both down to Earth with a crash.
Dark Phoenix of course survives the impact unharmed, although the same can't be said for Nova. But now he has to face Hope Summers and Scarlet Witch, who get him reeling. Beast, Cap, Iron Fist, Iron Man, Storm, Thor and Wolverine arrive by jet and join in.
The joint attack starts to break the Phoenix's hold on Scott Summers. He remembers the ideals that he tried to live up to, and temporarily begs the Avengers to kill him. Later a vision of Jean Grey, his dead love and the previous Dark Phoenix, tells him to give up. As Hope and Wanda continue to pummel him, they see the Phoenix Force leave his body. But only to take over its original target Hope.
The new Phoenix flies around the world, followed by Iron Man. He sees her calming the forces that Cyclops unleashed, and repairing damage. Then she returns to the Himalayan gathering (rejoined by Hulk and joined by Rachel Summers). She is clad in a white version of the Phoenix costume, and says that as White Phoenix she will lead the world into paradise, as the Cyclops and the rest of the Phoenix 5 tried to do but failed.
But Wanda persuades her that this isn't her destiny. She was created not to use the Phoenix Force but to give it up. The 2 women join hands and forces and say "No more Phoenix". The Phoenix Force leaves Hope and spreads over the globe. The Stepford Cuckoos see Cerebra showing new mutants springing up all around the world. Spider-Man is about to rescue a girl from a dangling train when she sprouts wings and rocky(?) skin and saves herself.
Later, Cyclops has survived the affair, and is imprisoned in a ruby quartz prison cell. He tells Cap that he accepts responsibility for all he did, including killing Charles Xavier and nearly destroying the world. Apparently the rest of the Phoenix 5 are on the run (and it seems Magneto too).
Cap admits that he was also partly at fault. He should have done more to help mutants earlier. He intends to do something to rectify that. And we see Hawkeye and Scarlet Witch probably reviewing possible members of the new Uncanny Avengers team.
There is also the unspoken suggestion that if the Avengers hadn't tried to stop Hope becoming the Phoenix at the start of this series, then the rebirth of mutants would have happened without all the fighting.
We also see Black Panther and Storm not talking to each other while Wakanda is rebuilt. Iron Fist asks Tony Stark if he'd figured out all along what would be the outcome of letting Hope and Wanda loose. Thor invites Nova to be an Avenger. Wolverine prepares a eulogy for Prof X. And Hope is in the ruins of Utopia, which has been cordoned off by SHIELD.