Zeus calls all the gods to assembly. He says that, now that Achilleus has come back to the fight and is super mad, he's worried that Troy will be conquered before its time.
He tells the gods that they have now free rein to get involved—just to make sure things don't get out of hand.
So down they go: Athene, Hera, Poseidon, and Hermes on the Achaians' side; Ares, Apollo, and Artemis on the Trojans'.
Apollo takes the form of Priam's son Lykaon and urges Aineias to take on Achilleus. "Come on," he says, "we all heard you boasting you could do it when you were drunk. Now's the time!"
Aineias says, "I fought him once before—and he would've beat me if it weren't for the help of the gods."
But then Apollo says, "You're the son of Aphrodite. Achilleus is the son of Thetis—a lesser divinity. If you take him on, you can beat him."
That's all Aineias needs to hear. Now, fired up, he charges after Achilleus.
Hera, who has been watching all this, asks Poseidon if they should intervene.
Poseidon says, "Nah. Let's just wait and see if any of the other gods, like Ares or Apollo, try to start something. If they do, we'll make short work of them."
So they sit down on the sidelines—probably chomping on some ambrosial peanuts and crackerjacks.
Achilleus and Aineias approach each other for combat.
Achilleus asks, "What's your problem? You think if you kill me you'll be some sort of big man or something? Back off, buddy."
But then Aineias says, "Me back off? Check out my family tree." He then proceeds to recite, in great detail, his family tree—and then concludes, "But enough talk. Let's fight."
They throw their spears. Aineias's spear deflects off Achilleus's shield. Achilleus's spear punches through the shield of Aineias, but passes over his shoulder.
Then Achilleus draws his sword and runs at Aineias, who lifts up a huge rock and prepares to defend himself.
Poseidon, looking on, turns to Athene and says, "We should save Aineias. He shouldn't have to die just because Apollo tricked him into thinking he could take Achilleus. Besides, he's always given us sacrifices—and he and his descendents are destined to survive."
(This reference to the future of Aineias's descendents is the hook on which the Roman poet Virgil would later develop the legend of the Aeneid. According to this version, Aineias—or "Aeneas," as his name is spelled in Latin—and a small band of Trojans survived the fall of their city, and eventually made it to Italy, where they founded the precursor to the city of Rome. You can read all about their exciting adventures in Shmoop's guide to Virgil's Aeneid.)
In reply, Hera says, "Whatever. Do what you want."
At that, Poseidon walks over, drifts a mist over Achilleus's eyes, picks up Aineias, and carries him over to the sidelines of the battle, where he drops him. Then he tells Aineias to stay out of the frontlines of battle for as long as Achilleus is alive. Once he's dead, Poseidon says, Aineias can have at it.
Then Poseidon goes back to Achilleus and takes the mist off his eyes. Achilleus is decidedly nonplussed to find his enemy gone, but he accepts it, figuring that some god must have interfered.
He urges the Achaians into battle.
On the other side, Hektor is encouraging the Trojans.
Apollo approaches Hektor and tells him not to go head-to-head against Achilleus. If he does, Apollo says, he will be killed. Hektor merges into the ranks of his army.
Achilleus is fighting in the front of his army, killing many Trojans.
After Achilleus kills Hektor's brother, Polydoros, Hektor loses it. He rushes in to attack Achilleus against Apollo's orders.
Achilleus is pleased to see him coming, and tells him to "Bring it on."
In response, Hektor tells Achilleus that he knows how tough he is—but all it will take is one lucky blow with a spear to bring him down.
(Compare Hektor's observation to that of the preacher in the Biblical book of Ecclesiastes: "I returned and saw under the sun, that the race is not to the swift, nor the battle to the strong, neither yet bread to the wise, nor yet riches to men of understanding, nor yet favour to men of skill; but time and chance happeneth to them all." For a comparison of alternative translations of this passage (9:11), check out this website.)
The problem is, luck only goes so far. Sometimes the gods just aren't with you. Thus, when Hektor throws his spear at Achilleus, Athene blows it away.
But when Achilleus then tries to get Hektor, Apollo swoops in and pulls him out of harm's way.
Achilleus realizes the jig is up—for now—and goes on to kill other Trojans in gruesome fashion.