Outside, assembled Plebeians demand an explanation for Caesar's death. Cassius leads half of them away while Brutus stays to address the others. Brutus explains that he loved and honored Caesar, but loved Rome more, and killed Caesar rather than let every Roman become a slave. The people are persuaded by his rhetoric and proclaim Brutus a hero. One even cries "Let him be Caesar" (3.2.47)
Brutus's speech rests on two points: that Caesar was ambitious, and that he would have made slaves of all Romans. Both ideas are assumptions, but Brutus speaks of them as fact. The cry of the last plebeian shows that some citizens would be happy to have a king.
Antony has entered with Caesar's body in a coffin. Brutus departs, turning the pulpit over to Antony. The crowd denounces Caesar and continues to laud Brutus.
It's incredibly foolish of Brutus to leave now—he's seen how easily the people's minds can be changed.
Antony says that he has "come to bury Caesar, not to praise him" (3.2.71). He says that the conspirators who claimed Caesar was ambitious are all honorable men, but then gives examples of Caesar acting in non-ambitious ways. When Antony pauses to weep, the crowd begins to say that Caesar was murdered unjustly.
Antony's opening line exemplifies his tactic: to announce the opposite of his true intentions. Antony calls the conspirators "honorable," because the crowd supports them, but slowly renders the term sarcastic by illustrating their mistakes.
Antony regains his composure, and says he has no intention of wronging the honorable Brutus and Cassius, or inciting the mob to riot. He mentions that he's found Caesar's will, which would make the people venerate Caesar if they knew its contents, but that he dare not read it. The Plebeians clamor to hear it. Antony descends to stand over Caesar's coffin.
Weeping provides time for the plebeians to interpret Antony's hints—the same trick Cassius uses. Rioting is precisely what Antony wants, but again he claims the opposite. He pretends to mention the will accidentally, to seem unskilled at speaking.
Antony describes Caesar's murder in graphic terms, and then uncovers Caesar's body. The crowd is ready to hunt down and kill the conspirators, but Antony bids them stay. He maintains that he does not wish to incite them to violence, and that he is not as well-spoken as Brutus.
Caesar's body adds strength to Antony's argument. He pretends to hold the crowd back, but only wishes to stir them up more. His claim of being less well-spoken than Brutus is clearly untrue.
Antony finally reads Caesar's will, which promises a sum of money to every citizen, and announces the conversion of Caesar's property into public parks. The crowd leaves in a frenzy, intending to kill the conspirators and burn their homes. A servant of Octavius enters to say that Octavius has arrived in Rome, and is waiting for Antony with Lepidus at Caesar's house. He adds that Brutus and Cassius have fled Rome.
Caesar's will seems to prove that he really did love the people. Octavius apparently ignored Antony's instructions, coming to Rome before word was sent. Shakespeare manipulates time here—in actual history, Brutus and Cassius actually remained in Rome for a year after Caesar's murder.