When Thor debuted in the pages of Journey Into Mystery #83 in 1962, readers may have thought of these as the continuing adventures of Thor, God of Thunder. While Thor had somehow become magically intertwined with a man named Donald Blake, the basic structure remained the same: Thor defending Earth from fantastic beasts, with gods and magic often involved.
But Thor was truly born a superhero when Avengers #1 was released in September 1963. He was no longer a god, humbled by an enchantment, doing dramatic deeds. He became part of a team, working with humans in a way never before seen in myth, or in comic books. Thor working with Iron Man, Ant-Man, The Wasp, and The Incredible Hulk, elevated those heroes to the level of demi-gods; his willingness to cooperate showed him to be even closer to humanity than his alter-ego Donald Blake could.
Like in the 2012 Avengers film with which you may be more familiar, the first Avengers comic brings the team together to defeat Loki.
Having previously been re-imprisoned following the events of Journey Into Mystery #94 (and this is not the first escape from a sentence imposed in Journey Into Mystery #88), Loki decides to use his magic powers to make trouble for Thor on Earth, and uses an illusion to cause The Incredible Hulk to damage railroad tracks with a train approaching. Hulk manages to repair the tracks before the train arrives, but the passengers see this as evidence of a rampage by the infamous, terrifying Hulk.
Bruce Banner’s friend Rick Jones, who was present at the incident which created the Hulk, hears of this and tries to find someone to prevent a catastrophe – he knows that Bruce Banner, the man trapped inside the Hulk, means no one any harm.
Jones reaches out to the Fantastic Four via ham radio, to no avail. Loki diverted the call to Donald Blake’s radio, and he transforms into Thor to stop the Incredible Hulk. But he wasn’t sufficiently selective – the call made its way to Tony Stark, the Iron Man, and to Hank Pym and Janet Van Dyne, the Ant-Man and the Wasp. They all fly from New York to the US Southwest to stop the Hulk.
The heroes all meet at the meeting place of the Teen Brigade, a group of young heroes of which Rick Jones is a member. They discuss Jones’s suspicions that Hulk isn’t the rampaging monster the media suspects, but Thor suddenly leaps off in the middle of conversation. He’s seen the Hulk, but only a mirage created by Loki. When his comrades tell him the Hulk wasn’t there, he realizes who must be behind this entire incident.
While Thor returns to Asgard to seek Odin’s permission to deal with Loki, Iron Man, Ant-Man, and the Wasp locate the Hulk. They engage him in battle in an attempt to subdue him. But after Thor defeats a troll Loki had convinced to protect him on his prison island, he took Loki with him to where the others were fighting the Hulk, explaining how his magic-wielding brother was able to deceive them all.
After Thor returns Loki to Odin to find a more secure prison, the group, now five strong, including Thor, Ant-Man, the Wasp, the Incredible Hulk, and Iron Man, meet one last time. Ant-Man and the Wasp suggest they found a team so that they can come together to face especially dangerous threats. Janet Van Dyne suggests the team call themselves “The Avengers”, or something like that, which they all agree sounds awesome. And they all head home to their own comic books, until the next issue of The Avengers.