Cassius and Brutus clash as civil war breaks out.
Characters: 
Brutus

Brutus is leading an army and is upset with Cassius for hiring less-than-honest soldiers. Later, he sees the ghost of Julius Caesar.

Lucilius

A man loyal to Brutus who warns him that Cassius is upset with him.

Pindarus

A soldier and servant of Cassius serving as a messenger for him.

Cassius

Cassius is leading an army, and is angry with Brutus for having disciplined one of Cassius' men.

Soldiers

Soldiers in the armies of Brutus and Cassius.

Poet

An old poet breaks into the military camp to chastise Brutus and Cassius for fighting with each other.

Messala

A noble Roman who reports to Brutus and Cassius that Antony, Octavius and Lepidus have put a hundred senators to death.

Lucius

Brutus' young servant attending him in his military tent and playing music for him.

Titinius

A noble Roman attending Brutus and Cassius.

Varro

Soldier of Brutus attending him in his military tent.

Claudius

Soldier of Brutus attending him in his military tent.

Caesar’s Ghost

The ghost of Caesar warns Brutus of an impending defeat.

Scene Summary: 

Civil war has broken out in Rome, with Brutus and Cassius leading one side, and Antony and Octavius leading the other.

Brutus is with his army in the field. Cassius arrives, and the two men argue and lob accusations at each other. 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. An old poet barges into the camp, and tries to convince the two men to stop fighting with a simplistic poem before he is thrown out. Brutus and Cassius have wine together in Brutus’ tent, and Brutus tells Cassius that Portia killed herself by swallowing hot coals.

Titinius and Messala enter with news that Cicero has been killed on Antony’s orders, along with many other senators. The men discuss their plans for battle at Philippi. Brutus and Cassius swear friendship, and Cassius departs, leaving Brutus alone with his guards. After his guards fall asleep, the ghost of Caesar appears, calling himself Brutus’ evil spirit. Brutus is startled and wakes the others, who noticed nothing. Brutus gives orders to Varro and Claudius to tell Cassius begin the march on Philippi first.