Synopsis by Van Plexico
Thanos has a new scheme: Instead of merely becoming God (as he attempted earlier, via the Cosmic Cube), he wishes to destroy every star in the universe. Why? In order to please the new love of his life: DEATH. Through such an offering, he hopes to prove himself worthy to be Death's mate.
At first, Thanos's only opposition comes from Adam Warlock. Still the troubled spirit, Warlock has entered into a limited alliance with Thanos (along with Pip the Troll and Gamora) dating back to Warlock's own series, when they opposed the Magus. But Warlock uncovers Thanos's vile scheme, and he, along with Captain Mar-Vell, alert the Avengers.
The Assemblers have all gathered at the Mansion on a stormy night, sensing big things are about to happen. Suspicious of Warlock at first, they eventually board a quinjet and fly out to meet Thanos's starship, "Sanctuary."
Of course a massive battle ensues, mostly between the Avengers and Thanos's alien minions. Warlock engages Thanos in single combat and is slain. Mar-Vell watches as the soul gem absorbs Warlock's own soul, carrying it to Soul World inside the gem, where Warlock encounters everyone else who has ever been absorbed by the gem, now all living in contented hapiness.
In the meantime, Iron Man destroys Thanos's star killer weapon, but then Thanos returns to the main battle, rallies his troops, and defeats the Avengers. At one point, Thor, Mar-Vell, and Iron Man fly through space after Thanos, only to be blasted by Thanos's huge energy weapon. Thus subdued, the Avengers are imprisoned in a stasis chamber, displayed like trophies aboard Sanctuary.
With the big guns out of action, Moondragon is just able to send a telepathic call for help to the Earth, where it enters a sleeping Peter Parker's dreams and alerts him to the danger. Racing to the Baxter Building, he finds the Thing as the only resident at home. Naturally suspicious of Spidey anyway, Grimm is particularly dubious of the strange dream he describes. But the two warm up one of Reed Richards's new vehicles and speed into space anyway.
Of course, there they encounter Sanctuary, and are sucked aboard the huge vessel. (There are several similarities between this story and Star Wars, even though both came out about the same time.) Battling alien critters, Ben and Spidey eventually find Thanos and the imprisoned Avengers. Ben is laid low by the mighty Thanos, but Spidey manages to elude his pursuers and then destroy the stasis device with the biggest, heaviest object he can find--himself! As Thanos watches in shock, the Avengers roar out of the chamber after him. Thor proclaims, "You now face Thor, god of thunder!" Ben adds, "And the Thing, idol of millions!"
Even so, Thanos has the heroes on the ropes, until, unwittingly guided by Lord Chaos and Master Order, Spider-Man lashes out, knocking over the globe which encases Warlock's Soul Gem. Warlock blazes out of the gem to full size, now a fearsome apparition of flames. Thanos gawks at him, as Warlock reaches out, and FLASH! Thanos is turned to stone. Warlock, his mission complete, returns to the Soul Gem.
With Thanos defeated, the aliens are quickly rounded up and disarmed. Spidey expresses surprise that they will be released, but Mar-Vell points out that Earth's jails could never hold so many odd creatures.
The Avengers "bury" Warlock, with a touching tombstone inscription: "Here lies Adam Warlock: Godslayer, Savior of two worlds, and tormented soul. May he now find peace."
Lord Chaos and Master Order sum things up for Thanos: "He is entrapped in the petrified remains of his own corruption, lamenting the waste he has made of his days, and weeping for a love unfulfilled."