On the plains of Philippi, Octavius and Antony discuss the situation. Octavius says the enemy is planning to attack, contrary to what Antony had suggested. Antony replies that they are just putting on a false show of courage. The two men prepare for battle, although they disagree on tactics. Antony wants Octavius to take the left side of the field, while he takes the right. Octavius wants it the other way around.
Before the battle begins, Octavius, Antony, Brutus and Cassius meet and trade insults. Cassius reproaches Brutus for sparing Antony's life. If he had not done so, they would not now have to listen to his aggressive words. Octavius says he will not stop until Caesar's death is avenged. Cassius denounces him as a schoolboy who does not deserve the honor of being killed by Brutus; he also insults Antony's love of revelry. Antony and Octavius depart, ready for battle.
Cassius tells his servant Messala that it is his birthday. He also tells of an omen: as they journeyed from Sardis, two eagles swooped down and perched on their banner. The eagles remained there all the way to Philippi. But that morning they departed. In their place are ravens, crows and kites, which look down on Cassius's army as if they were prey. He fears that this is a bad omen. Messala urges him not to believe it, and Cassius says he only partly does, and he is fresh and ready for battle.
Cassius tells Brutus that if they lose this battle, this will be the last time they speak to each other. He asks what Brutus would plan to do in such a situation. Brutus says he does not intend to commit suicide. Cassius asks him if he would allow himself to be led in triumph through the streets of Rome. Brutus says this will never happen. They bid each other an affectionate farewell.
Antony and Octavius are supremely confident. The focus of the scene is on Brutus and Cassius, who contemplate the coming battle with a sense of fatalism. Although they do not say it outright, they fear they will be defeated.