Agamemnon is unable to sleep because of his concern about the fate of the Achaian army. After much tossing and turning, he rises and awakens all his senior commanders. Old Nestor advises that under cover of darkness a scout be sent into the Trojan camp. With luck, this maneuver will enable them to learn the strengths, as well as the plans, of the enemy.
Diomedes volunteers to reconnoiter behind the Trojan lines, and he selects Odysseus to accompany him. The two men arm themselves and set out. In the area between the camps, they capture Dolon, a Trojan nobleman who was sent by Hektor to conduct a reconnaissance of the Achaian camp. The warriors promise Dolon that they will not harm him and from him they learn the whereabouts of Hektor and his staff, key information about the various units of the Trojan army, and the precautions that the Trojans have taken to guard the camp. Diomedes then treacherously kills the Trojan spy. The two Achaian heroes also learn that a new contingent of troops from Thrace lies asleep and unprotected on the Trojan flank. They kill many of these warriors until Apollo intervenes.
After returning to camp the two warriors take a ritual bath.
