Synopsis
This opens like an issue of Guardians of the Galaxy, explaining why they turned up at the end of last issue.
Some days ago the 5-person team were protecting a planet from the Badoon. The Badoon claimed to have been sent there by Thanos, to keep the Guardians away from Earth. So the Guardians got here as fast as they could.
Here in Avengers Tower various Avengers and Guardians renew acquaintanceships. But Black Widow slips away to deal with a wound she got in the recent battles. And Hawkeye slips out to help her. Clint comments on their long friendship, Natasha kisses him and he kisses back. But then Widow pulls away commenting that he has a girlfriend.
The other Avengers tell the Guardians what's been happening. Drax and Star-Lord think Thanos might be after the Infinity Gems. Captain America and Iron Man uncomfortably admit that the Gems are on Earth but swear they're well hidden. Thanos' daughter Gamora is sure her father doesn't know the Gems are here, or he'd come directly for them himself.
Gamora and Peter Quill explain what they think Thanos is doing. He wants a planet as a base, and he's always fancied Earth. But recently a Galactic Council declared Earth off-limits, because it is a volatile place. Partly because of previous alien meddling, Earth has access to cosmic powers. And the alien invasions have disrupted our normal progress.
Before taking over the world Thanos needed to take certain cosmic weapons away from us (and maybe use them himself). But because of the quarantine he couldn't do it himself, hence his empowering the Zodiac as lackeys.
The Avengers know that Zodiac successfully retrieved 1 item in #1. Cap takes Hulk to see Gen'l Whedon and 'persuade' him to say what was taken. It turns out the army had created a Cosmic Cube. Tony Stark downloads the details.
Tony and Rocket Raccoon have converted a quinjet for interstellar flight. The Avengers then accompany the Guardians in Star-Lord's Ship.