While the Iliad is concerned with the larger story of the Trojan war, the work itself only covers a short part. Two months, in the ninth year of a ten year war, to be precise.
The Iliad focuses on the falling out between Agamemnon and Achilles. After returning the captive woman Chryseïs to the Trojans, Agamemnon ultimately takes Briseïs, another captive, from Achilles.
Achilles takes this as a sign of severe disrespect and withdraws from the conflict, prolonging the stalemate between the Achaians and Troy. Not until his friend Patroklos is killed, wearing Achilles’ armor, does Achilles decide to return to conflict to avenge his death.
Achilles kills Hektōr, a Trojan prince, and parades the corpse around the walls. Ultimately, Achilles is convinced by Zeus to return the body to King Priam for ransom. The Iliad closes with Hektōr’s funeral.