The story opens many years ago in Jotunheim, as Thor and Loki battle a group of Storm Giants. When Thor protects his brother, Loki accuses Thor of robbing him of his own victory. When the battle is over, Thor silently reflects that this was the same place where he once fell through a mystical crevice, which led to his confrontation with Hercules in THOR ANNUAL #1. While that portal has since been sealed, Loki coincidentally wanders into another cavern, despite Thor’s warnings for him to stop.
Thor follows Loki through the cavern. After he has lost sight of Loki, Thor decides to explore one of the many branches of the cavern in search of his brother. As he continues through the cave, Thor walks through a strange mist. When he emerges in a forest, he realizes that he has forgotten who he is. Unknown to Thor, he has travelled through both time and space to ancient Troy. Thor follows the sound of a wounded boar and ends up rescuing a hunter who turns out to be Aeneas, son of Aphrodite and hero of the epic THE AENEID.
Aeneas tells Thor that his people have come as allies to the Trojans as they defend their city against the attacking Greeks. Aeneas recounts the history of how the beautiful Helen was married to Menelaus, but ran off with Prince Paris to Troy, starting the Trojan War, which is now in its ninth year (all of this coming from THE ILIAD). Aeneas leads Thor back into Troy through a secret tunnel, just as Paris and Menelaus are about to face off in single combat to decide the fate of the war. During the battle Menelaus gains the upper hand, and begins dragging Paris back to the Greek lines by his helmet. Paris prays to Aphrodite, who, unseen by all but Aeneas and Thor, saves Paris by causing his helmet strap to break. When he is free from Menelaus’s grip, Aphrodite grabs Paris and returns him to Troy to be healed. With Paris having lost, the Trojans begin to make arrangements for a peaceful surrender.
Seeing Aphrodite jogs Thor’s memory, and he realizes not only who he is, but that he has been misplaced from the proper time as well. Thor follows Aphrodite to Olympus, where Zeus and the other gods are watching and discussing the war below. Hera and Athena, who are on the side of the Greeks, are trying to convince Zeus that Troy must be destroyed when Aphrodite returns. Zeus chastises Aphrodite for breaking his command that no Olympian interfere in the war. When, in his anger, Zeus obliterates a nearby mountaintop, Thor exclaims his amazement at Zeus’s power, which reveals his presence. Thor explains that he did not mean to intrude on Olympian affairs, and merely came to this time and place accidentally. While Zeus and Thor sort things out, Athena takes advantage of the distraction and travels to Troy, where she tricks a Trojan soldier named Pandarus into firing an arrow at Menelaus, shattering the truce.
As the battle picks up again, gods on both sides intervene in the battle below. Athena aids the Greeks while Aphrodite aids the Trojans. When Aphrodite is wounded, she convinces Ares to seek revenge for her. Thor, being mistaken for Apollo, intervenes to save his friend Aeneas from Diomedes. Thor’s involvement enrages Zeus, who transports Thor to the top of nearby Mount Ida.
On Mount Ida, Thor and Zeus battle relentlessly. Thor is shocked when Zeus catches Mjolnir, and Zeus is equally shocked when Mjolnir breaks from his grip to return to Thor’s hand. As Thor and Zeus battle, months pass in Troy below, during which time many key events from THE ILIAD unfold. Finally, Zeus asks why Thor continues to fight merely for the sake of Aeneas, and Thor reveals that he fights on only for the glory of Asgard. If Asgard’s mightiest warrior fails, Thor explains, Zeus will lead his forces against Asgard. Zeus vows not to attack Asgard, as he and Odin have an ancient truce, and their skirmish ends.
Thor says goodbye to Aeneas, and returns to the forest where he originally emerged. As he approaches the cavern, Thor is met by Loki. Thor then admits that he forgot all about Loki, and asks what he has been up to all this time. Loki states that he, too, lost his memory for some time. He then explains how he met a crafty Greek prince named Odysseus, and together they conceived of the Trojan Horse! The comic ends with a final panel that reveals the sack of Troy.