Avengers, The (1963 series) #396

In Captain America #449 Zodiac troops covered Manhattan with a force-field dome to screen it from the influence of the stars. They chased Captain America who sought out Thor and found him depowered and with Enchantress.
In Thor #496 the 3 fought the Zodiac troops but failed to stop a portal opening to bring in more troops.
In Iron Man #326 Cap and Thor linked up with Teen Tony Stark who only had the gauntlets of his new Iron Man armour working so far. They captured a Zodiac sky-skimmer with a portal generator on it. Other Avengers were outside the dome.

Now the trio are on the sky-skimmer looking out at Deathcry and Quicksilver on the ground beyond the dome and Giant-Man and Wasp hovering above them in a quinjet. Below them crowds throng the Brooklyn Bridge desperate to escape. Our 3 can use the tech on the skimmer to open a temporary gap in the bridge, but they can't decide whether to let some of the crowd out or let the Avengers in.

Tony uses the dwindling power of his chestplate to energise the transporter device on the skimmer and open quite a large portal. Hank Pym flies the quinjet through, but that's a mistake because Zodiac's anti-technology field causes it to fail. Human-size mutated Wasp gives him a lift clear of the falling craft and Thor hurls Mjolnir to knock it into the river. Meanwhile some civilians are able to surge through off the bridge, and Deathcry has to leap out of the way with Quicksilver and into the dome.

Stark's chestplate has died and his heart's failing. Pym wants to drain the remaining energy from the transporter to repower the chestplate, but if he does the portal will close with people halfway through it. Janet van Dyne can't stand to lose another Tony Stark so soon after the previous 1, so she uses the wind from her wings to drive people back from the hole. Giant-Man saves Tony and the crowd blames the Avengers for trapping them again. Quicksilver zooms off to search for Zodiac's base of operations.

Meanwhile we look inside a Force Works Hex-Ship flying over the Grand Canyon where we find Hawkeye and Scarlet Witch. They are heading from the FW base in California to the Avengers Mansion in Manhattan but can't make contact with it. Then they get a message from Dum Dum Dugan of SHIELD asking them for help with the Hulk. But before they can respond a military helicopter decloaks and brings their ship down with a plasma-particle beam. But that's a story for next issue.

In New York Quicksilver has found the Zodiac base on the deactivated WWII aircraft carrier Intrepid and called in the others. Teen Tony has donned a makeshift mask and accompanied Cap and Giant-Man in a stealth invasion. Unfortunately they are spotted and surrounded. As Zodiac's leader prepares to order them shot Quicksilver gets him with a big gun set on stun. Then the Avengers, now including Deathcry, Thor and Wasp, attack.

But then Zodiac's real leader shows up, calling himself Libra. This oversize being can control his density (like Vision) so is able to take on (the nigh-on-powerless) Thor and Quicksilver and then Deathcry. He also rants that the dome cuts of the population from zodiacal influence and hence their destiny is now his to command. And 1st Manhattan then the world.

Libra next tackles Wasp and Cap. But Henry Pym has sneaked off during the battle to search the ship. Now he emerges very giant-size carrying the large transformer that generates the dome, and smashes it to pieces. The dome vanishes and all the tech-stuff starts working again.

But Libra claims that his test has proved successful. He detonates bombs in all his troops uniforms and then takes his leave, vowing to return when the rest of Zodiac are ready.