Synopsis
This issue mainly follows the Maximum Security event adventures of the team of Avengers Reservists (Moondragon, Photon, Quasar, Starfox (Eros of Titan), Thor and Tigra plus non-Avenger Jack Of Hearts) who gathered together on the other side of the Galaxy in the Av: Infinity mini-series to oppose the Infinites. In Thor #30 they followed Eros' advice and stopped of at a space-bar to celebrate and so were away from Earth when it was quarantined in MaxSec#1, and there the Galactic Patrol tried to arrest them. In MaxSec#2 they were contacted by Wasp who told them what was going on, and they said they'd look for allies outside the quarantine barrier.
Which is why they're now at the spaceport of the planet Seliander which hosts the Intergalactic Council which initiated the quarantine, demanding to see Shi'ar Majestrix Lilandra Neramani, a long-time friend of Earth. They are escorted down to the planet and into the presence of Lilandra and the Council. (The Ruul who we know are behind Earth's troubles have decided it would be incautious to try to prevent them.) Spokesperson Photon is diplomatic and even Thor holds his tongue but Moondragon lashes out angrily, forcing the Majestrix warn her to be civil.
Lilandra then explains what happened and why. Humanity has gained a reputation for meddling unbidden in intergalactic affairs, so the Council decided to quarantine the Solar System to protect their member worlds. Also they decided to declare Earth a prison planet and dump alien criminals there. The criminals would keep the humans too busy to try to escape, and the humans will likewise contain the prisoners. She says that she spoke on Earth's behalf but could not sway the Council. Moondragon challenges Lilandra to trial by combat but the Majestrix says that is part of Shi'ar law and the Council isn't bound by it. But she says she'll ask the Council to hear their appeal.
Later in their guest quarters Jack Hart (JOH) and Wendell Vaughn (Quasar) talk about the little Earth things they've missed in their long sojourns in space. Recent companions-in-fun Greer Grant (Tigra) and Eros are worried about not being allowed home. Heather Douglas (Moondragon), Monica Rambeau (Photon) and Thor hold a council of war. Heather senses Lilandra means what she says, but she can't read the minds of the mysterious Ruul aliens. And Monica is sure the Council will ignore them. Thor says they must give the Council the chance to show they are honourable. If not they could contact allies like the Rigellians and the Starjammers, and he could raise the armies of Asgard.
Then Moondragon senses they are being spied on. But when she exposes the spy 4 other aliens attack, but are quickly dealt with. The group head for the Council Chamber to complain but on the way they are attacked by more vicious aliens which Moony senses are a variety of Ruul. She can also read these Ruul's minds easier, but she's KO'd before she can say what she's found. The rest battle on until they are subdued by a gas. Thor is the last standing be even he succumbs because the gas is absorbed by his skin rather than being breathed in.
The tension is broken by a short interlude in New Mexico. where Peggy Chandler reads a magazine article about the latest Avenger Triathlon, and sees him fighting aliens in the Maximum Security event. She also has a file folder of cuttings about the 3-D Man, and starts the drive to New York to get answers.
The cosmic Avengers awake to find themselves constrained by shackles that negate their powers. And then the Kree Supreme Intelligence addresses them from a screen. Now awakened Moondragon can at last tell the others that she discovered that the Ruul were actually Kree. And the Supremor feels it's safe to tell his captive audience (and us) the whole plan.
The Kree are a successful warrior-race but they have reached an evolutionary dead-end and would eventually be surpassed by other races. So the SI decided to do something about it. (And he's been trying ever since the end of the Kree-Skrull War in Avengers #97.) He was successful (in the Operation Galactic Storm event) when he detonated a Nega-Bomb which in the short-term left the Kree ruled by the Shi'ar but in the long-term would allow them to resume evolving. However this would take a long time, and a quicker solution later presented itself.
At the end of the Avengers Forever limited series the Supremor gained possession of the Forever Crystal which had allowed Immortus an unprecedented ability to manipulate time and timelines. The SI used it to instantaneously evolve some Kree into the Ruul, and individual Ruul have the ability to adapt themselves to suit the requirements of a task, eg diplomacy or battle. Afterwards the Crystal vanished into space-time, but its job was done.
The SI did all this while imprisoned by SHIELD on the Earth's Moon, and he's still there now. But he sent the Ruul to ingratiate themselves with other Galactic races, and he himself mentally freed Ego The Living Planet (who had been devoured by the bio-verse Super-Ego in Thor #450) and sent him on the mad rampage that triggered the Maximum Security event (in MaxSec: Dangerous Planet).
The result was the quarantining of the Solar System with a forcefield generated by Watchtowers controlled by the Ruul, and its use as a prison planet. But the SI secretly sent the Ego-Spore to Earth fully intending it to take over the whole world. It will kill all the humans, ending their future threat to the Kree, and Ego will be reborn. But the Ruul have erected power-spires around the globe and these will siphon Ego's power to the surrounding Watchtowers, giving the Kree the most potent weapon in the universe.
But the Supremor needs the Council not to stop what's going on until it's too late. So he'll destroy all life on a Shi'ar world and leave these Avengers there with their minds wiped clean to take the blame for the atrocity, and harden the Council's heart even further.
Then he breaks contact and the laughing Ruul guards leave them. But Quasar manages to send a quantum warning message to Earth.
And on Earth the current Avengers (Goliath, Scarlet Witch, Triathlon, Vision, Warbird and Wasp, without Iron Man but with Captain America and the recovered Wonder Man) are told by US Agent (flanked by their liaison Duane Freeman with Valerie Cooper and Henry Peter Gyrich of the Commission On Superhuman Activities) that he has Federal authority to recruit all superheroes including the Avengers to join his army of alien prisoners to take the fight to the enemy (in MaxSec#3).