Two tribunes, Flavius and Murellus, find scores of Roman citizens wandering the streets, neglecting their work in order to watch Julius Caesar’s triumphal parade: Caesar has defeated the sons of the deceased Roman general Pompey, his archrival, in battle. The tribunes scold the citizens for abandoning their duties and remove decorations from Caesar’s statues. Caesar enters with his entourage, including the military and political figures Brutus, Cassius, and Antony. A Soothsayer calls out to Caesar to “beware the Ides of March,” but Caesar ignores him and proceeds with his victory celebration (I.ii.19, I.ii.25).
Cassius and Brutus, both longtime intimates of Caesar and each other, converse. Cassius tells Brutus that he has seemed distant lately; Brutus replies that he has been at war with himself. Cassius states that he wishes Brutus could see himself as others see him, for then Brutus would realize how honored and respected he is. Brutus says that he fears that the people want Caesar to become king, which would overturn the republic. Cassius concurs that Caesar is treated like a god though he is merely a man, no better than Brutus or Cassius. Cassius recalls incidents of Caesar’s physical weakness and marvels that this fallible man has become so powerful. He blames his and Brutus’s lack of will for allowing Caesar’s rise to power: surely the rise of such a man cannot be the work of fate. Brutus considers Cassius’s words as Caesar returns. Upon seeing Cassius, Caesar tells Antony that he deeply distrusts Cassius.
Caesar departs, and another politician, Casca, tells Brutus and Cassius that, during the celebration, Antony offered the crown to Caesar three times and the people cheered, but Caesar refused it each time. He reports that Caesar then fell to the ground and had some kind of seizure before the crowd; his demonstration of weakness, however, did not alter the plebeians’ devotion to him. Brutus goes home to consider Cassius’s words regarding Caesar’s poor qualifications to rule, while Cassius hatches a plot to draw Brutus into a conspiracy against Caesar.
That night, Rome is plagued with violent weather and a variety of bad omens and portents. Brutus finds letters in his house apparently written by Roman citizens worried that Caesar has become too powerful. The letters have in fact been forged and planted by Cassius, who knows that if Brutus believes it is the people’s will, he will support a plot to remove Caesar from power. A committed supporter of the republic, Brutus fears the possibility of a dictator-led empire, worrying that the populace would lose its voice. Cassius arrives at Brutus’s home with his conspirators, and Brutus, who has already been won over by the letters, takes control of the meeting. The men agree to lure Caesar from his house and kill him. Cassius wants to kill Antony too, for Antony will surely try to hinder their plans, but Brutus disagrees, believing that too many deaths will render their plot too bloody and dishonor them. Having agreed to spare Antony, the conspirators depart. Portia, Brutus’s wife, observes that Brutus appears preoccupied. She pleads with him to confide in her, but he rebuffs her.
Caesar prepares to go to the Senate. His wife, Calpurnia, begs him not to go, describing recent nightmares she has had in which a statue of Caesar streamed with blood and smiling men bathed their hands in the blood. Caesar refuses to yield to fear and insists on going about his daily business. Finally, Calpurnia convinces him to stay home—if not out of caution, then as a favor to her. But Decius, one of the conspirators, then arrives and convinces Caesar that Calpurnia has misinterpreted her dreams and the recent omens. Caesar departs for the Senate in the company of the conspirators.
As Caesar proceeds through the streets toward the Senate, the Soothsayer again tries but fails to get his attention. The citizen Artemidorus hands him a letter warning him about the conspirators, but Caesar refuses to read it, saying that his closest personal concerns are his last priority. At the Senate, the conspirators speak to Caesar, bowing at his feet and encircling him. One by one, they stab him to death. When Caesar sees his dear friend Brutus among his murderers, he gives up his struggle and dies.
The murderers bathe their hands and swords in Caesar’s blood, thus bringing Calpurnia’s premonition to fruition. Antony, having been led away on a false pretext, returns and pledges allegiance to Brutus but weeps over Caesar’s body. He shakes hands with the conspirators, thus marking them all as guilty while appearing to make a gesture of conciliation. When Antony asks why they killed Caesar, Brutus replies that he will explain their purpose in a funeral oration. Antony asks to be allowed to speak over the body as well; Brutus grants his permission, though Cassius remains suspicious of Antony. The conspirators depart, and Antony, alone now, swears that Caesar’s death shall be avenged.
Brutus and Cassius go to the Forum to speak to the public. Cassius exits to address another part of the crowd. Brutus declares to the masses that though he loved Caesar, he loves Rome more, and Caesar’s ambition posed a danger to Roman liberty. The speech placates the crowd. Antony appears with Caesar’s body, and Brutus departs after turning the pulpit over to Antony. Repeatedly referring to Brutus as “an honorable man,” Antony’s speech becomes increasingly sarcastic; questioning the claims that Brutus made in his speech that Caesar acted only out of ambition, Antony points out that Caesar brought much wealth and glory to Rome, and three times turned down offers of the crown. Antony then produces Caesar’s will but announces that he will not read it for it would upset the people inordinately. The crowd nevertheless begs him to read the will, so he descends from the pulpit to stand next to Caesar’s body. He describes Caesar’s horrible death and shows Caesar’s wounded body to the crowd. He then reads Caesar’s will, which bequeaths a sum of money to every citizen and orders that his private gardens be made public. The crowd becomes enraged that this generous man lies dead; calling Brutus and Cassius traitors, the masses set off to drive them from the city.
Meanwhile, Caesar’s adopted son and appointed successor, Octavius, arrives in Rome and forms a three-person coalition with Antony and Lepidus. They prepare to fight Cassius and Brutus, who have been driven into exile and are raising armies outside the city. At the conspirators’ camp, Brutus and Cassius have a heated argument regarding matters of money and honor, but they ultimately reconcile. Brutus reveals that he is sick with grief, for in his absence Portia has killed herself. The two continue to prepare for battle with Antony and Octavius. That night, the Ghost of Caesar appears to Brutus, announcing that Brutus will meet him again on the battlefield.
Octavius and Antony march their army toward Brutus and Cassius. Antony tells Octavius where to attack, but Octavius says that he will make his own orders; he is already asserting his authority as the heir of Caesar and the next ruler of Rome. The opposing generals meet on the battlefield and exchange insults before beginning combat.
Cassius witnesses his own men fleeing and hears that Brutus’s men are not performing effectively. Cassius sends one of his men, Pindarus, to see how matters are progressing. From afar, Pindarus sees one of their leaders, Cassius’s best friend, Titinius, being surrounded by cheering troops and concludes that he has been captured. Cassius despairs and orders Pindarus to kill him with his own sword. He dies proclaiming that Caesar is avenged. Titinius himself then arrives—the men encircling him were actually his comrades, cheering a victory he had earned. Titinius sees Cassius’s corpse and, mourning the death of his friend, kills himself.
Brutus learns of the deaths of Cassius and Titinius with a heavy heart, and prepares to take on the Romans again. When his army loses, doom appears imminent. Brutus asks one of his men to hold his sword while he impales himself on it. Finally, Caesar can rest satisfied, he says as he dies. Octavius and Antony arrive. Antony speaks over Brutus’s body, calling him the noblest Roman of all. While the other conspirators acted out of envy and ambition, he observes, Brutus genuinely believed that he acted for the benefit of Rome. Octavius orders that Brutus be buried in the most honorable way. The men then depart to celebrate their victory.