Last issue Triton the amphibian Inhuman arrived at Avengers Mansion to find the Avengers under attack by SHIELD Mandroids, under the direction of H. Warren Craddock whose Alien Activities Commission accuses the Avengers of collaborating with the Kree, because of their association with Captain Marvel.
The Mandroids have the Avengers on the ropes, when Iron Man (secretly their designer Tony Stark) disables them with well-judged blasts of electricity. The Avengers then turn their attention to Triton.
The Inhuman explains that he came to New York seeking help from the Fantastic Four, to prevent a war between his people and humans, but the FF are out of town. He now asks the Avengers for aid.
Triton tells how his king Black Bolt went to San Francisco to study Inhumans and determine how to integrate the Inhumans into the rest of the world. But Black Bolt's cousin Maximus gained expanded mental powers, with which he remotely gave Black Bolt amnesia and took control of the Great Refuge. And Maximus believes Inhumans should rule the world.
Triton and 3 others of the royal family escaped and went to San Francisco to find their leader. Triton got separated from the others, and has arrived here. Thor mentions that he recently tangled with Black Bolt and the other 3 in California.
The Avengers want to go find Black Bolt, but Vision thinks they should go after Captain Marvel, Quicksilver and Scarlet Witch who have been abducted by Skrulls to the Andromeda galaxy. He tells them he saw the Inhumans' city enclosed in an impenetrable barrier last issue.
The Avengers decide to split up, and Vision chooses the teams. Captain America, Goliath (with his growing power running out since last issue) and Rick Jones will go to San Francisco, while Thor will take the other powerful members Iron Man and Vision into space.
The designated team flies to California by quinjet where they find no-longer-amnesiac Black Bolt and his young human orphan friend Joey. The whole lot then fly to the Great Refuge.
On the way Black Bolt remembers back to his youth, where he overheard Maximus (now significantly referred to as his brother) meeting with a delegation of Kree faithful to Ronan the Accuser. The Kree said that when Ronan became leader of the their empire they would return to take over the Earth, and let their creations the Inhumans rule it for them. (Ronan wrested control from the Kree Supreme Intelligence in #89, so the time is now.)
Black Bolt further remembers how he used his vocal power to cripple the Kree flying saucer as it left. In panic brother Maximus lashed out with his mental power, but as a side effect made the Kree pilot lose control. The saucer crashed, killing their parents. This was when Maximus became 'the Mad'.
Meanwhile back in New York the remaining Avengers have been attacked again by the Mandroids. When they defeat them again, more easily this time, they discover that the men inside are unconscious, and the suits have now been operated by remote control.
Vision has now had a change of heart. He realises that he let his love for Wanda direct the mightiest Avengers towards saving her, when the Earth is in peril from Maximus and the Kree. So now he tells Thor to take him and Iron Man to the Great Refuge via a Mjolnir space-warp.
Once there Thor tries to penetrate the barrier dome surrounding the city. But Mjolnir just passes through it and then returns, with no effect. Then the quinjet arrives, and Black Bolt shatters the dome with his voice.
The Avengers face an Inhuman army. But a whisper from Black Bolt shatters Maximus' mental spell, and the army switches sides. The Avengers attack Maximus and some Kree allies. The Kree flee in their saucer, but not before grabbing Rick Jones. Maximus returns to a child-like state.
At then end of the issue Black Bolt prepares to return to San Francisco with Joey, to bring his cousins home. And the captive Supreme Intelligence on the Kree homeworld surveys the scattered players, including Captain Marvel building an Omni-Wave weapon for the Skrulls to save the lives of Quicksilver and Scarlet Witch (as seen last issue), and watches his plans coming to fruition.