The Achaians, under King Agamemnon, have been fighting the Trojans off and on for nine years, trying to retrieve Helen, the wife of Menelaos, and thus Agamemnon's sister-in-law. Paris, a son of the king of Troy, kidnaps Helen, who becomes the legendary "Helen of Troy" and "the woman with the face that launched a thousand ships."
Yet, after years of Achaian attacks, Troy remains intact, and the Trojan army remains undefeated. The same cannot be said for the Achaian army. At present, the Achaian troops are dying from a mysterious plague. Hundreds of funeral pyres burn nightly. Finally, Achilles, the Achaians' most honored soldier, calls for an assembly to determine the cause of the plague.
A soothsayer reveals to the army that King Agamemnon's arrogance caused the deadly plague; he refused to return a woman who was captured and awarded to him as a "war prize." Reluctantly, Agamemnon agrees to return the woman, but, as compensation, he says that he will take the woman who was awarded to Achilles, his best warrior.
Achilles is furious, and he refuses to fight any longer for the Achaians. He and his forces retreat to the beach beside their ships, and Achilles asks his mother, the goddess Thetis, if she will ask Zeus, king of the gods, to help the Trojans defeat his former comrades, the Achaians. Zeus agrees to do so.
The two armies prepare for battle, and Paris (the warrior who kidnapped Menelaos' wife, Helen) leaps out and challenges any of the Achaians to a duel. Menelaos challenges him and beats him, but before Paris is killed, the goddess Aphrodite whisks him away to the safety of his bedroom in Troy.
A short truce is called, but it is broken when an over-zealous soldier wounds Menelaos. During the battle that follows, Diomedes, an Achaian, dominates the action, killing innumerable Trojans and wounding Aphrodite, a goddess.
The Trojans seem to be losing, so Hektor returns to Troy to ask his mother to offer sacrifices to Athena. She performs the rituals, but Athena refuses to accept them. Meanwhile, Hektor discovers Paris safe in his bedroom with Helen, and shames him into returning to battle. Then Hektor visits with his wife and their baby son. It is clear that Hektor is deeply devoted to his family, yet feels the terrible weight of his responsibility as commander-in-chief of the Trojan army.
During the fighting that continues, the Achaians begin to falter, and at one point Athena, Zeus' daughter, fears that the entire Achaian army may be slaughtered. Thus, she and Apollo decide to have Hektor challenge one of the Achaian' warriors to a duel in order to settle the war. Telamonian Aias (Ajax) battles Hektor so valiantly that the contest ends in a draw, and a truce is called.
During this break in the fighting, the dead of both armies are buried and given appropriate funeral rites, and the Achaians fortify their defenses with a strong wall and a moat-like ditch.
The fighting resumes, and so many Achaians are slaughtered that Agamemnon suggests that his troops sail for home, but finally he is convinced that he must return to the fighting. Messengers are sent to Achilles, asking him to return to battle, but Achilles is still sulking beside his ships and refuses to fight.
Soon Agamemnon, Diomedes, Odysseus, and old Nestor are all seriously wounded, and Achilles realizes that the Achaians are in danger of imminent defeat. Therefore, he sends his warrior-companion, Patroklos, to find out who the seriously wounded are.
Patroklos talks with old Nestor, one of the wisest of the Achaian soldiers. Nestor asks Patroklos to dress in Achilles' armor and return to battle. The Achaians, he says, will rejoice and have new faith in their death struggle against the Trojans when they think that they see Achilles returning to the battle. In addition, the Trojans will so fear the wrath of the mighty Achilles that they will be easily defeated. Patroklos promises to ask Achilles for permission to use his armor and ride into battle disguised as the mighty warrior.
Meanwhile, Hektor leads a massive Trojan surge against the Achaian wall that stands between the Trojans and the Achaian fleet of ships, and the wall is successfully smashed. The tumult is so deafening that hell itself seems unloosed.
Achilles is watching and realizes that his wish may be granted: The Achaians are about to be annihilated. He sends Patroklos into the fighting, disguised as Achilles himself. The Achaian army rejoices at what they think is the return of Achilles to the fighting, and the Trojans are so terrified that they are quickly swept back to the walls of Troy.
Patroklos' valor seems superhuman. He has killed nine Trojans in a single charge when Apollo strikes him with such fury that Hektor is able to catch him off-guard and thrust a spear through his body. Then some of the most intense fighting of the war follows in a battle to claim Patroklos' body. Finally, the Achaians rescue Patroklos' corpse, and Hektor captures Achilles' armor. Then the Achaians return to the beach, guarding their ships as best they can.
Achilles is filled with overwhelming grief and rage when he learns that his warrior-companion, Patroklos, has been slaughtered. His mother, Thetis, comes to him and advises him that it is fated that he will die if he tries to revenge Patroklos' death. But she says that if Achilles decides to revenge Patroklos' death, she will outfit him in a suit of new armor, made by one of the gods.
Achilles chooses: He will defy certain death and the Trojans in an attempt to punish them for what they (and he) did to Patroklos. Thus, he returns to battle in his new armor and is so successful that he and the Achaians rout the Trojans. He savagely kills Hektor, the Trojans' mightiest warrior. Achilles' anger is not sated, however. He ties Hektor's corpse to his chariot and circles Patroklos' burial mound every day for nine days.
Hektor's parents are so grieved at the barbaric treatment given to their son's corpse that Priam, Hektor's father, goes to Achilles and begs for his son's body. Achilles is moved by Priam's pleas and by the memory of his own father. Consequently, he agrees to cleanse and return Hektor's body.
Hektor's body is given the appropriate cremation rites, and then with mourning and weeping for the noble warrior, the Trojans place his remains in a golden casket and place it in a burial barrow.