This issue marks the final conflict (until 'The Rebirth of Thanos' storyline in Silver Surfer in 1990 and then the (Infinity Gauntlet') between Adam Warlock and Thanos, resulting in both their deaths.
Adam Warlock arrives in a desert planet, tottaly destroyed by Thanos, and found Gamora left behind, near death. After she tells him that Thanos was a crazy god that only wants to destroy the World, Warlock absorbs her into his Soul Gem and goes towards a place on Earth - Avengers Mansion. There is Iron Man, Vision, Scarlet Witch, Beast, Captain America and Thor, acting as normal as they could be. Suddenly, Captain Marvel and Moondragon arrives, brought by a cosmic call. Then Warlock also arrives and tells everyone about the menace they are all about to battle - Thanos, and tells them all about the mad titan. After Captain Marvel had destroyed the Cosmic Cube, at Captain Marvel #33, Thanos was left alone in space, abandoned even by his lover Death, but he was rescued by his spaceship and them found about the Infinity Gems and their power. The first gem he gets from the Stranger, the second in a satelite-prison from a alien race, the third in a cave in a world called Deneb IV, the fourth he gets after killing a monster called Xiambor, the fifth at the Earth's Moon left behind by the Gardener, and finally the sixth gem he founds with Adam Warlock. At Warlock #10, Thanos use Adam Warlock to defeat his enemy Magus and with this brief alliance could get the powers of the Soul Gem, and with the power of the six Infinity Gems, he criate a powerfull new gem for himself.
Suddenly the Starcore comander calls the Avengers, telling that a huge army of spaceships is about to destroy the Earth, and the Avengers fly to space to try to stop it. Thousands of spaceships are coming to Earth, but the Avengers never quit. Thor and Iron Man tries to destroy every ship in the way of Moondragon's spaceship, while they try to reach the center of command. There they all fight more and more enemies, until Captain Marvel found Warlock and a zombie Pip, left behind by Thanos. Warlock steal Pip's soul and get know about Thanos plans. He and Marvel go after the mad titan in the Sun.
At Thanos's spaceship, Warlock flies towards the huge ray-gun to stop the Sun from exploding, Captain Marvel tries to fight Thanos but is also defeated, but Iron Man and Thor arrive and destroy the Gem of Thanos. After Thanos leaves, a new Adam Warlock arrives and get the soul of the old, dead Warlock into his Soul Gem, where he should leave in peace after all, with Gamora and Pip.
Continued in Marvel Two-in-One Annual #2 - Death Watch!