After nine days of plague, Achilleus calls the Achaians to assembly.
When the soothsayer Kalchas is afraid to speak his mind, Achilleus backs him up.
When Kalchas says that Agamemnon has to return the captive daughter of Chryses, Agamemnon insists on taking the girlfriend of one of the other Achaians.
Achilleus argues against this, and they get into a huge shouting match, which results in Agamemnon saying he's going to take Briseis, Achilleus's girlfriend.
Achilleus considers killing Agamemnon, but the goddess Athene comes down and stops him.
Instead, Achilleus tells everyone that he quits. He says they'll all be sorry when they're suffering at the hands of Hektor, the greatest Trojan warrior.
Then Achilleus goes back to his own ship to hang out with his best friend Patroklos.
When the heralds come from Agamemnon to take Briseis away, Achilleus welcomes them. He tells them his quarrel isn't with them, and he lets them take her.
Then Achilleus starts crying. He prays to his mom, the sea-goddess Thetis, to come to him.
When she arrives, he asks her to make Zeus help the Trojans so that all the other Achaians will realize how much they need Achilleus. Thetis grants his request.
The Trojans start giving the Achaians hell. After a particularly bad day for the Achaians leaves the Trojans encamped on the plain, Nestor suggests they ask Achilleus for help. Agamemnon agrees.
Odysseus, Phoinix, and Aias go to bring Achilleus the message; they find him chilling out in his shelter with his best friend Patroklos, playing the lyre. He welcomes them warmly and offers them dinner.
But when the three chieftains present Agamemnon's unbelievably generous offer of gifts, Achilleus flat out rejects it.
He only wavers on one thing: at the beginning of the scene he tells the emissaries his plan to sail home the next day. At the end, he says he'll think about sailing home the next day.
Of course, Achilleus doesn't sail home the next day. Instead, he spends his time watching the battle from the stern of his ship, which has been drawn up on shore.
When he sees Nestor riding back to camp with the injured healer Machaon, he sends Patroklos to confirm the wounded man's identity.
Patroklos goes and finds out that it was, in fact, Machaon. Then he gets an earful from Nestor about how the Achaians aren't doing so well. Nestor suggests that Patroklos should dress up in Achilleus's armor and lead the Myrmidons – the nation Achilleus commands – into battle.
By the time Patroklos reaches Achilleus, he has also had to help out the injured Eurypylus, and has seen that the Trojans are attacking the Achaians' ships. He is now in tears.
Achilleus makes fun of Patroklos for crying, but then agrees to let him lead the Myrmidons.
He makes Patroklos promise only to fight the Trojans off the ships, but not drive them back toward the city. Achilleus is worried that that would make him look bad.
Of Course, Patroklos does drive on to the city, which results in him being killed by the tag team of Apollo, Euphorbos, and Hektor. Hektor strips Achilleus's armor from the body.
When Achilleus gets the message that Patroklos is dead, he falls on the ground like a dead man.
Antilochos (the guy who delivered the message) holds Achilleus's hands to make sure he doesn't kill himself.
Then Achilleus lets out a terrible cry, which reaches his mother, Thetis. She comes and finds him.
Achilleus says he has lost the will to live unless he can kill Hektor.
Thetis reminds Achilleus that, if he kills Hektor, he is doomed to die soon afterward. Achilleus says, "Let me die then."
He vows to patch things up with Agamemnon and return to the battle on the side of the Achaians.
Thetis makes him wait a day while she goes off and gets him new armor from the god Hephaistos.
In the meantime, Iris, the messenger of the gods, convinces Achilleus to go stand outside the Achaians' wall. His appearance, plus his three fearsome shouts – amplified by the goddess Athene – put so much fear into the Trojans that they turn tail and run. This gives the Achaians time to retrieve the body of Patroklos.
When the body returns to the Achaian camp, Achilleus laments over it. That night, he swears not to bury Patroklos until he has killed Hektor.
The next morning, Thetis comes and gives Achilleus his armor. She finds him still weeping over Patroklos, worried the body will disintegrate. Thetis infuses it with some divine substances to preserve it.
Then, Achilleus refuses to eat breakfast with the other Achaians, he is so eager to go to battle and start killing Trojans.
Achilleus arms for battle with the other Achaians and rolls out in his chariot.
In the battle, Achilleus kills many Trojans. He almost kills Aineias, but the god Poseidon saves him.
He almost kills Hektor, but the god Apollo saves him.
Then Achilleus pins the Trojans against the River Xanthos (a.k.a. the River Skamandros). He drives a bunch of guys into the river and kills them there. Then he drags twelve Trojans out of the river and takes them prisoner.
At this point, he sees the Trojan warrior Lykaon climbing out of the river. Some time ago, Achilleus had captured Lykaon and sold him into slavery. But then somebody bought him back and gave him his freedom.
Lykaon begs Achilleus for mercy, but Achilleus says, "Tough luck." He kills Lykaon and throws him into the river.
After Achilleus kills another man, Asteropaios, and throws him in the river, the river gets angry.
Skamandros (the god of the river) tells Achilleus to stop clogging his body with corpses.
Achilleus says, "Fine. But I'm going to keep killing lots of Trojans."
When Achilleus overhears Skamandros complaining to Apollo, he decides to take on the river. This doesn't go so well, and it's only when Hephaistos intervenes with a huge blast of fire that the river backs down, thereby saving Achilleus.
Undeterred, Achilleus keeps killing lots of Trojans and drives them toward the city. He would have captured it, but Apollo tricks him by taking the form of a Trojan warrior and leading Achilleus on a wild goose chase over the plain, giving the Trojans time to get their act together.
When Apollo lets Achilleus know he's been duped, Achilleus heads back toward the city. There he finds Hektor alone outside the walls.
He chases Hektor three times around the city's perimeter. Finally, the goddess Athene tricks Hektor into making a final stand.
Hektor makes an offer to Achilleus: whoever wins the fight can keep his opponent's armor, but he has to give his body back to his home city. Achilleus rejects the offer.
They fight, and Achilleus gives Hektor a mortal wound in the throat. Achilleus rejects Hektor's request to spare his body from the dogs. Achilleus says he wishes he were angry enough to hack off Hektor's flesh and eat it raw. Then Hektor dies.
After the Achaians show up and each stabs Hektor's body, Achilleus pierces the corpse's heels and threads leather thongs through them. Then he drags Hektor from his chariot back to the Achaian camp.
Back in the camp, Achilleus keeps lamenting over Patroklos.
When he finally falls asleep, the ghost of Patroklos appears to him and tells him he needs to be buried. Patroklos requests that, when Achilleus dies, their ashes should be mixed together in one urn. Achilleus tries to embrace him but the ghost vanishes.
The next day, Achilleus holds a funeral for Patroklos. He slaughters the twelve captive Trojans on top of Patroklos's pyre.
Then Achilleus hosts funeral games in commemoration of Patroklos. He gives out impressive prizes to the winners. At the final competition, a spear-throwing contest, he graciously gives first prize to Agamemnon before the game begins.
After the funeral, Achilleus keeps grieving for Patroklos. Whenever he gets really frustrated, he hitches up Hektor's corpse to his chariot and drags him three times around Patroklos's tomb.
The gods think this is way out of line and send Thetis down to tell Achilleus to give Hektor's body back to King Priam. They also tell Priam to go ask for it.
When Priam arrives, alone and unarmed, in Achilleus's tent, the two men recognize an unspoken bond between them.
Priam asks to go immediately with his son's body, but Achilleus refuses. He says, "I know the gods sent you. Don't annoy me or I'll lose my temper and kill you."
Then Achilleus goes out of the room and tells the servant-women to bathe and clothe Hektor's body. He tells them to do it where Priam won't be able to see it. He doesn't want to see Priam get upset, because then he might get upset and kill him against the gods' orders.
Then Achilleus and Priam share a meal.
At the end of the meal, Achilleus promises Priam that he will hold the Achaians to a truce for however many days are needed to bury Hektor. Priam requests eleven days. They shake on it.
Then Priam goes out to sleep on the porch. Achilleus goes to sleep beside Briseis.