Having banqueted in Agamemnon’s tent, Hector & Co. next head for Achilles’ tent for additional roistering. There, in Achilles’ tent, Achilles tells Patroclus that he plans to fatten up Hector for the massacre that is to occur tomorrow (Hector and Achilles have promised to engage one another in one-on-one combat) when Achilles receives a message from Queen Hecuba of Troy and her daughter, Polixenes, reminding Achilles of his vow to cease warring against Troy in return for Polixenes’ love. Achilles resolves to honor that vow.
Anon, Hector & Co, accompanied by Agamemnon & Co., arrive at Achilles’ tent. Agamemnon and Menelaus bids Hector goodnight and retire for the night. Diomedes excuses himself to attend to some business, and Troilus, attended by Ulysses, follows Diomedes. Hector and the rest of his party enter Achilles’ tent. Meanwhile, Thersites, who has helped Achilles prepare his tent for the roistering and who has exchanged insults with Patroclus, follows Diomedes, suspecting that Diomedes is up to no good.
Troilus and Ulysses, not to mention Thersites who is off on his own, keep themselves at a distance and in hiding as Diomedes exchanges words with Cressida. Diomedes’ and Cressida’s seeming intimacy upsets Troilus to an extent that Ulysses is eager to have Troilus removed from the ground lest Troilus resort to a desperate measure that would endanger his--Troilus’--life. Troilus refuses to go, however, promising that he will outwardly remain calm, no matter his inner turmoil. Then the unthinkable happens: Cressida gives Diomedes Troilus’ sleeve, a token that Cressida would do well to keep in her possession if she values her faith and loyalty to Troilus. Shocked by what he has seen, Troilus wonders if he had imagined it all. When Ulysses affirms that what Troilus has seen was real, Troilus tells Ulysses that he had loved Cressida, that he will now consider Cressida the very exemplar of falsehood in women, and that Diomedes will pay the price should he dare flaunt the sleeve, Troilus’ token of love, in the battlefield. All the while, Thersites confirms his suspicion that Cressida has been playing the whore with Diomedes. Anon, Aeneas appears to inform Troilus that the Trojan princes are now heading back to Troy.
Hector’s wife, Andromache, who has had nightmares of Hector’s slaughter, tries to dissuade Hector from fighting today--to no avail. She is joined by Cassandra, who corroborates the omen, and by Priam who is moved to dissuade Hector likewise on account of Hecuba’s nightmare with regards their son. However, for honor’s sake, Hector will not heed their warnings. It’s a decision seconded by Troilus who chides their sister, Cassandra, dismissing her premonitions as hysterics. Troilus chides Hector too however. He chides him for being too merciful in the battlefield, of refusing to strike a Grecian when he’s down. Hector argues that it’s only fair play, and presently, having received Priam’s blessings, goes to the battlefield. Troilus is about to go the battlefield himself when Pandarus appears with a letter from Cressida. Troilus reads the letter only to tear it up. He doesn’t believe a word of Cressida as her deeds have shown that she favors Diomedes--Diomedes who will by and by be the object of Troilus’ unmitigated rage.
Eager to see Troilus slaughter Diomedes for a whore (as he so deems Cressida), Thersites goes to the battlefield. Typically, Thersites’ inner thoughts reflect a cynically blasphemous mind as he disparages Nestor, Ulysses, and Achilles. We learn from Thersites, however, that Ajax has grown as proud as Achilles with the result that even Ajax is now refusing to suit up and fight. Presently, Thersites observes, to his pleasure, Troilus giving chase to Diomedes when Hector comes upon him and demands a just account of his worth. Thersites pleads for his life, arguing that he’s a mere lackey and a scurrilous one at that. Hector believes him and leaves.
Diomedes commissions a servant to take Troilus’ horse and show it to Cressida and thereby prove that he--Diomedes--has vanquished Troilus. But this is scarcely the truth as Troilus is alive and well and has proven, along with Hector, to be the scourge of the Greeks. Because of Troilus, who has killed a friend of Ajax, Ajax is suiting up to do battle. Indeed, the Trojan success on the battlefield which has the Greeks in full retreat, is turning out to be a godsend (to the Greeks) as Patroclus’ death has awakened Achilles’ wrath who demands that Hector answer for Patroclus' death.
While Troilus does battle with both Ajax and Diomedes, Hector faces off with Achilles. But because Achilles is out of practice, Hector offers Achilles reprieve which Achilles grudgingly accepts. They will meet again when both are at full strength--or so Hector believes. Presently, Hector meets Troilus who informs his brother that Ajax has taken captive of Aeneas. Troilus resolves to free Aeneas or die in the attempt trying and as he does so, Hector gives chase to an elaborately armored Greek who refuses to stand and fight.
Determined to kill Hector, Achilles instructs his Myrmidons, his personal fighting force, on how they will ambush and encircle Hector. Meanwhile, Thersites cheers on for Paris as the adulterer is engaged in a swordfight with the cuckold, Menelaus. His entertainment is cut short, however, when he is challenged by Margarelon, Priam’s bastard son. Not surprisingly, Thersites sues for peace and then runs for his life.
Having slain the elaborately armored Greek, Hector removes his armor when he is encircled by Achilles and his Myrmidons. Hector urges Achilles to forego his advantage as he--Hector--is unarmed, grossly outnumbered, and all but retired for the day. Alas, Achilles exhorts his Myrmidons on and Hector is slaughtered. Achilles is about to apply the fatal sword thrust when trumpets sound, signifying the retreat of both the Greek and Trojan armies. In lieu of the sword thrust, Achilles will have Hector dragged in the wake of his chariot.
The news of Hector’s death at Achilles’ hands spreads like wildfire through the Greek camp. Ajax counsels solemnity, arguing that Hector was as a good a man as Achilles. Agamemnon orders Achilles to be sent to his tent. With Hector’s death Troy’s fall is deemed imminent.
Aeneas proclaims that the day has been a good one for Troy when Troilus breaks the bad news. Hector has been slain most cruelly by Achilles. Arguing that Troy’s fall is now imminent, Troilus entreats the gods to make the fall mercifully quick. Aeneas objects to this assessment which prompts Troilus to add that vengeance will be their solace, vengeance against Achilles as soon as day breaks the first thing tomorrow. As the Trojan princes and nobles march into the city, Pandarus engages Troilus to no avail. Troilus shuns the old man. Alone, Pandarus laments his office as lovers’ go-between which is fated to be unappreciated and even loathed when all is said and done.