
Brutus and his followers rest briefly in the field. Brutus asks each in turn to help him kill himself to avoid capture. Clitus, Dardanius, and Volumnius all refuse, and when Antony’s troops approach, they run away. Strato agrees to hold Brutus' sword while he runs on it, and Brutus thus commits suicide. Antony and Octavius, with their forces and some of Brutus’ captured men, find Strato and the dead Brutus. They ask what happened, and Antony says that Brutus’ suicide was in line with his noble nature.

Brutus’ forces are still fighting. Cato’s young relative is killed. Some of Antony’s forces find Lucilius, who lies and says that he is Brutus. Antony’s men present the captured Lucilius to Antony, who immediately recognizes that he is not Brutus, but admits that he is nonetheless a worthy Roman captive.

Cassius is dismayed at cowardice among some of his own soldiers. Titinius brings discouraging news about Brutus’ army, and Pindarus arrives and says that Mark Antony has made his way into Cassius’ camp. Cassius asks Titinius to take his horse and find out whether a group of soldiers are friends or enemies, and tells Pindarus to climb a hill and report on how the battle is going. Pindarus sees a group of men surrounding a dismounted Titinius, and Cassius asks him to stop looking and help him kill himself. Pindarus stabs Cassius and runs away.

Brutus tells Messala to take part of the army to attack Octavius’ forces, sensing weakness on the enemy side.

Antony and Octavius squabble before meeting Brutus and Cassius in the field for a parley, and Octavius resents being told what to do by Antony. Brutus and Cassius arrive with their armies and each side accuses the other of merely making a show of bravery. Antony and Octavius leave, and Brutus consults with Lucilius while Cassius consults with Messala. Cassius reveals that it is his birthday, and that while he is not generally prone to believing in omens, he believes that seeing vultures follow the army to Philippi and then depart means that they will be deafeated.

Brutus is with his army in the field. He asks Lucilius how his meeting with Cassius went, and is dismayed to learn that Cassius seemed to be acting coldly. Cassius arrives, and Brutus asks to speak privately. Cassius complains about Brutus disciplining one of Cassius’ subordinates, and Brutus in turn accuses Cassius of taking bribes. Brutus argues that they must wage war honorably, or the killing of Caesar was hypocritical. Cassius contends that a practical approach is the only way to win the war.