Cassius observes Brutus advancing, and predicts the defeat of his troops, because they are advancing unevenly and without support. Immediately after expressing this fear, Cassius' attendant Pindarus enters, expressing alarm at how close Mark Antony's men are to Cassius' camp. Pindarus' entrance strikes a chord with Cassius, who then commands Titinius to ride into the fray below and determine what has happened. Cassius and Pindarus retreat to a high hill and Pindarus narrates the action below to a hiding Cassius. When Pindarus misinterprets what he sees below, and tells Cassius that Titinius has been captured, Cassius despairs and commands Pindarus, a longtime slave, to kill him. Pindarus does so, and then runs from the battle in grief over his actions.
Meanwhile, Titinius has dismounted below to greet friendly soldiers and has not been taken at all. As Pindarus exits, Titinius and Messala re-enter with a laurel from Brutus to Cassius, saying that Octavius has been overwhelmed by Brutus, just as Cassius has been overwhelmed by Antony. When they see Cassius lying dead on the ground, they realize that Cassius feared Titinius' death so much that he willingly misconstrued what happened below.
Messala goes off to notify Brutus' party of what has happened. Meanwhile, Titinius expresses grief over Cassius' death, and kills himself with the same sword. Brutus enters with his officers, including Messala, Young Cato, Strato, Voluminus, and Lucillius. Brutus sees the two men dead and proclaims that Caesar is still mighty because of the fallout from his death.
