Résumé: Outside the walls of Troy a delegation of Achaeans meets a delegation of Trojans for a prisoner exchange. Antenor is returned to the Trojans while Thoas of Aetolia, sans nose, is returned to the Achaeans. Cressida is also given to the Achaens, despite the efforts of Troilus to stop her from getting into Diomedes's chariot. Hektor, fearing to upset the delicate truce, takes control of Troilus's chariot.
In the Achaean camp, the leaders of the army are struck by Cressida's beauty and take turns kissing her. When her fear causes her to strike Odysseus, Diomedes steps in and takes her to the hut of her father, Kalchas. Cressida reveals to Kalchas that she wants to return to Troy because she loves Troilus. But Kalchas is only alarmed by this since he believes Troy is doomed. He urges Cressida to become Diomedes's lover.
Back in the city Troilus is equally in despair. He mopes near Pandarus's house by night. In an attempt to help Troilus forget his sorrow, Pandarus next day accompanies Troilus to a feast given by Sarpedon of Lykia. But it doesn't help.
Returning to battle, Troilus recognizes Diomedes as the Achaean who drove away with Cressida. Troilus kills one of Diomedes's chariot horses and hacks at Diomedes's sword arm, but loses his own chariot to Diomedes.