According to SparkNotes, "The Iliad" chronicles events during the final year of the battle for Troy, centering around the conflict between the Greek hero Achilles and the Trojan hero Hector. After initially sitting out of the fight, Achilles becomes enraged at Hector's slaying of a dear friend and lays waste to the Trojan forces before killing Hector himself.
In the beginning of the poem, Achilles has a dispute with the Greek leader Agamemnon over a slave, and as a result, retires from the battlefield and even prays for the Greeks to lose. Zeus aids the Trojans, and the tide of the battle begins to turn against the Greek forces. Achilles finally allows his friend Patroclus to borrow his armor and stand in for him on the field, but Apollo helps Hector slay the Greek warrior. Achilles sees the folly of his pride and returns to the battle with a fresh suit of armor forged by Hephaestus and demolishes the Trojan forces in pursuit of a fleeing Hector. Eventually Hector turns to fight, and Achilles slays him and desecrates his body, dragging it for days in sight of the Trojan walls. Eventually, Hector's father, King Priam, appeals to Achilles to allow them to bury his son, and Achilles relents and allows Hector a funeral.