Synopsis
Several of the Avengers Unity Squad have sent their minds back in time to occupy their current bodies, and they have stopped the Apocalypse Twins from creating a future where Earth is destroyed by a Celestial and only mutants survive to populate a new planet. But the destruction of the Twins' Tachyon Dam allowed Kang and his time-lost gang to invade, and Kang started to absorb the power of the Celestial - the power to conquer the universe.
Now various current characters are being defeated by by Kang's gang, who consider their options now that their future timelines no longer exist. As Iron Man 2020 (Arno Stark, but not the 1 in the current IM issues) faces Iron Man (Tony Stark) he blames Kang for his vanished home, but believes everyone has no choice but to obey him now. Our Dr Doom refuses to be anyone's servant, but Dr Doom 2099 believes that Kang has outsmarted them all. And the Earth X Venom (May Parker) reminds us that Kang's centuries-long plot has resulted in only 1 future timeline remaining, that of the Kang Dynasty.
In space Thor reappears from the coruscating energies of the dead Celestial Exitar, shrugging off the body of the Abomination Deathlok that had dragged him there. He attacks Kang with the axe Jarnbjorn (that he'd used to mortally wound the Celestial), but the Conqueror's new power enables him to hold the Thunder God at bay, and then throw him away.
We last saw Havok and Sunfire on the Apocalypse Ark destroying the Tachyon Dam, but now they are here to stop Kang drinking in more Celestial energy. Havok uses his own remaining energy to hit Kang with a cosmic blast. Then the duo dive into the bleeding wound to absorb the Celestial energy themselves, expecting it to kill them.
But Kang follows them and manifests an energy blade to stab Sunfire through the heart. Shiro Yoshida disintegrates, and the blast destroys Alex Summer's space helmet, scarring the left side of his face. (He can still breathe because the planet-sized Celestial has its own atmosphere.)
Iron Man 2020 is still fighting Iron Man. He makes the contradictory claim that if he serves Kang faithfully his future timeline will survive. Arno claims that Tony would do the same. Captain America disagrees, until Magistrate Braddock hits him with a psychic knife to the head. But Cap sees help arriving.
It's Immortus and his Infinity Watch, 1 of whom turns out to be the original Captain Marvel. Immortus leaves the Watch to fight Kang's Corps, while he himself goes after the Conqueror.
Kang asks Havok to submit to him, or he'll never see his (and Wasp's) (future) daughter Katie again - Kang has her secreted outside of time and space. But Alex knows he can't trust the villain, and he tells himself the only chance to get Katie back is to defeat Kang. So he uses the Celestial energy he has absorbed against him - but Kang has eaten even more of it.
But now Shiro reappears as Sunfire the Atomic Knight, his body apparently composed completely of Celestial energy. His 1st act is to blast Kang, and then the Apocalypse Twins' Ark, which explodes (we see Wolverine escaping in an escape pod).
Now Alex Summers uses his stolen energy to beat Kang up! Demanding his daughter back or he'll kill him. The villain does the 'how dare you lay hands on Kang' bit and then vanishes. On Earth the Infinity Watch are duelling with the Kang Corps when their opponents vanish away too. As Kang leaves he contacts his agent Ahab, the only Corpsman from this time period, leaving things up to him. (Presumably Ahab will be involved with Red Skull's upcoming Axis Event.)
Sentry and Wasp are also up near the giant Celestial. Sentry detects that Exitar is dead, his energy gone to the White Hot Room to await rebirth. He leaves the Solar System, taking the body far far away, but leaving behind the prediction that the other Celestials won't be happy. (The reborn Horseman of Apocalypse was somewhat unhinged, and has convinced himself he is the 'cosmic protector of humanity'.)
Jan returns to Earth to rejoin her fellow heroes and Immortus and the Infinity Watch. Suddenly Rogue falls to Earth, her head filled with the voices of all the heroes whose powers she borrowed last issue to fight Exitar with. Scarlet Witch makes the powers return to their owners. But Rogue had absorbed the whole of Wonder Man - he's composed completely of ionic energy. Now Wondie doesn't return, and Rogue still hears him in her head.
The new Sunfire flies down with disfigured Havok. Who has to tell Jan that their daughter is gone.
And part of the Ark has crashed in the Sahara Desert. 2 more Horsemen Daken and Grim Reaper emerge carrying the limp forms of Eimin and Uriel.