Juno, determined to see the war between the Trojans and the Latins begin in earnest, sends Iris to tell Turnus to attack the Trojan camp. The Rutulians surprise the Trojans, who react in fear to the approaching "mass ... of gloom and darkness" (45-46). Since Aeneas is not present (he is visiting the Etruscans, seeking their assistance in battle), the Trojans do as he had instructed, retreating behind their ramparts even though they feel ashamed to do so.
Turnus searches desperately for an entrance to the Trojan camp but, unable to find one, decides to set fire to the Trojan fleet. The attack is unsuccessful: years before, Jupiter's mother had given her pine grove to Aeneas for wood to build his fleet, and in return she had asked Jupiter to promise that no harm would ever come to her precious timbers. Although he questions whether mortals should be given immortals' privileges, Jupiter keeps his promise to his mother and transforms the burning ships into sea nymphs, who flee into the ocean's depths. The Rutulians are struck by fear at this sight, but Turnus maintains total confidence in his ability to defeat Aeneas. He will not, he states, hide himself in the belly of a wooden horse to prove his superiority to the Trojans; he will meet them "in broad daylight" (203).
Nisus and Euryalus, who had engaged in the footrace, now bravely volunteer to carry word of the attack to Aeneas, who is still in Pallanteum. Although Nisus initially tries to dissuade Euryalus from accompanying him, not wanting to put his friend in danger, Euryalus insists that he will have it no other way. Ascanius, struck by their courage, says that he will reward them richly upon their return, even though all that Euryalus asks is that his mother be provided for.
On the road, Nisus and Euryalus slay a number of Rutulians. Finally, however, they are spotted, and the Rutulian horsemen give chase through the forest. Euryalus, laden with spoils from those he slaughtered, falls behind, and he is captured by Volcens, a Rutulian warrior. Nisus makes a brave effort to save his friend, hurling spears at Euryalus's captors. In revenge for the deaths, Volcens kills Euryalus. Nisus rushes at Volcens in a rage and thrusts his sword through Volcens's mouth, but is then quickly slain by the other Rutulians.
The bereaved Latin men carry Volcens back to their camp, and then they place the heads of Nisus and Euryalus on pikes and parade them before the Trojans, who are deeply grieved by the sight. Rumor carries word of Euryalus's death to his mother, who weeps so piteously that the Trojans take her into their arms and carry her home. Angered by the deaths of their friends, the Trojans return the Latins' attack, and the battle begins in earnest. The next few pages describe great brutality: a wall collapses, killing many Trojans, and Ascanius makes his first kill in battle. He slays Turnus's brother-in-law, Remulus, because he had been mocking the Trojans. Apollo appears to Ascanius and tells him that while he has done well, he should never again engage in war, but instead must work to maintain peace.
Finally, the Latins manage to beat down the gate to the Trojan camp, although the Trojans are able to keep them out, and Pandarus, with superhuman effort, swings the gates shut once again. Several Trojans are left outside to battle the Latins, but Turnus had made it through the gate with the Trojans. He begins running rampant, killing all whom he encounters. Finally, Serestus and Mnestheus (who had engaged in the boatrace) shame their companions for allowing one man to create such discord. The Trojans finally get the upper hand and begin to close in on Turnus, but Juno sends word to him that he must flee. He escapes by jumping into the Tiber River and allowing the current to carry him back to the Latin camp.
In Book IX, the Rutulians - and Turnus in particular - demonstrate remarkable strength. Even though the outcome of the battle is certain, the Rutulians nevertheless reveal that they are extremely resourceful, courageous, able fighters, and they inflict a great deal of harm on the Trojan camp. Turnus is especially remarkable on the battlefield, holding his own even when he is the only Latin warrior locked inside the Trojan camp. Indeed, Turnus's character, like Dido's, derives its complexity from the fact that he is fated to lose, but is so confident in his abilities that he continues to battle destiny. He is clearly intended to be an antagonist, but Virgil allows readers to feel a measure of sympathy for this man, who is so certain in his convictions that he fights - almost heroically - to the very end.
Some of Virgil's critics even argue that Turnus appears almost more heroic than Aeneas, particularly in this Book. Throughout the Aeneid, Aeneas certainly demonstrates skill and valor, but is it truly heroic to fight when one is assured of success? Courageous, but heroic? It is a foregone conclusion that Aeneas will win the battle; the only suspense that Virgil can offer his audience lies in Turnus's remarkable abilities on the battlefield. This man is such a brilliant warrior that he has the ability to keep the inevitable victors at bay for far longer than they expected. By investing Turnus with exceptional abilities, Virgil heightens the suspense of the Aeneid and keeps readers' attention even though they know what the ultimate outcome will be.
One of the most poignant episodes here is the death of Nisus and Euryalus. These two men, who display a deep and enduring friendship (if not also romance, if one interprets homoeroticism in the poem), reveal the great reverence Virgil placed on such relationships. Nisus is a wholly self-sacrificing individual, willing to go on a highly treacherous journey by himself, so that he will not place his friend in danger, and later willing to sacrifice his own life to avenge the death of his friend. Euryalus is slightly less heroic; he appears to want to accompany Nisus largely so that he can share in the glory, but is caught by the Rutulians because he is so laden down with spoils taken from the bodies of his Latin conquests that he falls behind during a chase through the forest. Nevertheless, the connection that these two men share is admirable, and their shared death is undoubtably one of the most poignant, emotionally affecting moments in the tale.
Book IX is the only one in the Aeneid in which Aeneas is not directly present. Virgil does, however, indicate that Aeneas is such a strong character that his men continue to obey him - and even take on his characteristics - in his absence. Before leaving for the Etruscan camp, Aeneas instructed his comrades to retreat behind the battlements should the Latins attack, and even though it goes against their instincts as warriors to flee from battle, the Trojans do as their leader requested.
Aeneas's influence is underscored by the fact that many of the warriors display their leader's most notable traits during the battle: heroism, morality, and courage. Ascanius, in particular, is able to take over for Aeneas in his absence: as Aeneas might have done, he promises Nisus and Euryalus that they will be rewarded richly for their bravery, and he is struck by the piety of Euryalus's request that his mother be looked after. Furthermore, he makes his first - and only - kill out of a desire to protect the honor of his comrades, and he does so in a humble, relatively moral manner.