As dawn rises, Thetis arrives at Achilles’ camp with the new armor. Achilles is still in deep mourning, lying face down beside Patroclus’ body. The armor shines so brightly that the Myrmidons are afraid to look at it. Achilles thanks his mother.
The armor that Thetis brings to Achilles is not a part of the mortal world, but rather a piece of the supernatural. Only Achilles is fit to wear it.
Achilles calls an assembly of the Achaean troops. Agamemnon comes to the meeting, and Achilles says the time has come to reconcile. Agamemnon agrees, but notes that he is not to blame, indicating that Zeus's daughter Atë (Ruin) had blinded his judgment when he chose to quarrel with Achilles. Agamemnon then tells the story of Ruin, who was cast out of Olympus for foiling Zeus’ plans for Hercules. Agamemnon also tells Achilles that he will still give him the gifts he promised, including the return of Briseis. Achilles, knowing his time is short, indifferently accepts.
Achilles has decided to return to battle, and in doing so he has sealed his fate. He can no longer think of returning to his homeland in order to live a long and unremarkable life, or about spoils of war. Knowing that he will die, the ordinary aspects of Achaean life have lost their value, especially the treasure that Agamemnon had promised Achilles. It's as if he exists on a different, more heroic, plane than the other Achaeans. Agamemnon is still trying to save face, still being a politician. Achilles is focused purely on revenge.
Achilles urges the Achaean captains to call their troops to battle as quickly as possible. Odysseus replies that the men must eat first, so as to fortify themselves for battle. Agamemnon agrees, but Achilles says he has no taste for food until he satisfies himself in combat. Odysseus replies that food is for the living, and convinces Achilles to let the men eat. The captains sacrifice to Zeus and eat.
Achilles’ refusal to eat is a both a sign of his respect for Patroclus and an indication of his extraordinary eagerness to begin his killing. Odysseus’ statement is true, but Achilles almost has no need any longer for the necessities of men—his choice to fight has made him, essentially, one of the dead.
Agamemnon’s gifts are brought to Achilles’ camp. Briseis, returned to Achilles, sees that Patroclus has died and mourns over his body. She says that he was always very kind. Achilles’ comrades beseech him to eat something, but Achilles refuses, overfilled with grief. Achilles addresses Patroclus with a speech of mourning. Zeus, filled with pity, sends Athena to nourish Achilles with the food of the gods without him noticing.
The appearance of Briseis brings the plot of Achilles’ quarrel with Agamemnon full circle. Briseis’ lament is a sign of how much has changed since the initial argument of the captains. Now that Patroclus is dead, Briseis’ significance has diminished, as Achilles’ grief begins to elevate him above the realm of mortal things.
All the Achaeans prepare for battle. Achilles arms himself, donning the magnificent armor forged by Hephaestus. Achilles’ team of horses is readied. As Achilles mounts his chariot, Hera gives voice to his horse Roan Beauty. The horse tells Achilles that he will help save Achilles’ life today, but that the day of his death is soon approaching. Achilles is angered, saying that he does not need to be reminded of his fate. Achilles drives out to battle.
As Achilles’ prepares for battle, the sense of determined fate is deeply underscored. Even Achilles’ horses let him know that he must die soon, and Achilles seems tired of hearing about his future demise. Words no longer have any use for him: only action remains.