Scene i: The opening scene of the play is meant to establish the differences of opinion among the Roman citizens and the commoners regarding Julius Caesar. Caesar, who is extraordinarily popular among the common people, excites Rome when he defeats Pompey, who formerly possessed popularity among the Roman masses, in battle. However, not everyone is thrilled at Caesar's victory, as Flavius and Marcellus, among the elite of Rome, chastise the people for their celebration and proceed to tear down celebratory decorations, an act which will result in their arrest. The anger and mistrust of Caesar demonstrated by Flavius and Marcellus in this scene reflect the sentiments of the conspirators, who are disturbed by Caesar's rise to power and willing to risk punishment to stem it.

Scene ii: The action of the play begins in this scene. The first section of the scene begins with Caesar ordering Marc Antony to touch Calphurnia during the chariot race in an effort to cure their marriage of barrenness. Caesar's lack of a son is important because he wishes to become king and needs an heir. Octavius, Caesar's nephew, will also eventually become Caesar because of this, which is why he is involved in the triumverate. After this order, the soothsayer comes to warn Caesar to "beware the ides of March," or March 15. This is the first of several signs or omens that occur during the play, which brings about one of the play's central themes—fate and free will. In this case, Caesar dismisses the soothsayer as a "dreamer" and does not question him further about his warning, ignoring the sign being given to him. Caesar will ignore several other omens before his death in Act III due to his own ego, which also surfaces in this first section when he refers to himself in royal terms: "I hear a tongue shriller than all the music/Cry 'Caesar.' Speak. Caesar is turned to hear" (ll. 19-20). Although Caesar has a great deal of power, he is not a king, and his reference to himself as Caesar belies his great belief in his own power, for he is, as he puts it, "always Caesar."

In the second section of the scene, Cassius attempts to discern Brutus' position on Caesar as king. This introduces the conspiracy element to the play, as well as Brutus' love for both his friend Caesar and for his country. Unlike most of Rome, Brutus is not celebrating Caesar's victory because he knows that Caesar is almost certain to become king. Although Caesar is already Emperor, it is an appointed military position, and the Roman Senate is the body that holds the true power in Rome. By making Caesar king, Caesar would have absolute power for the rest of his life and then pass down that power to his heir, and the Senate would be at his mercy. Brutus, having been born a "free man," resists the tyranny that such an appointment could represent, although he loves and values Caesar as his best friend. Cassius also resists the idea of Caesar becoming king, but it is clear in this scene that Cassius resents Caesar's rise to power, especially considering that Caesar is epileptic, deaf in one ear, physically weak, and no greater than any other man. Cassius attempts to manipulate Brutus into participating in the conspiracy to come, using Brutus' love for the empire and his devotion to freedom as means. Brutus, however, is aware of the "dangers" into which Cassius would lead him, and hesitates until he learns from Casca that Marc Antony has tried to give Caesar a crown, which leads him to agree to meet Cassius the next day.

The failed coronation leads back to the nature of Caesar's character. As reported by Casca, Caesar is offered a laurel or coronet three times in this scene, and refuses all three times. The purpose of this, from Casca's view, is to win the crowd's approval. Caesar also knows that without the approval of the Roman Senate, the crown means very little, which is why Casca refers to the incident as "mere foolery." Caesar's action here is amplified by a sudden swoon, which leads the masses to feel sorry for him. (It is not clear whether this swoon is intentional or a result of epilepsy, but it is most certainly well-timed). Caesar's ability to manipulate the emotions of the Roman public establishes his position as a master politician while striking fear into his political opponents. This incident, combined with Caesar's popularity in the Senate and his military power, motivates Cassius into action and leads Brutus in the direction of the conspiracy.

Scene iii: More omens open this scene, which takes place during a powerful lightning storm. Casca, whose sour disposition would usually lead him to ignore fantastic events, trembles in fear of the storm, as well as several other strange occurrences happening throughout the city. He tells Cicero of a slave whose left hand burns unscorched, a lion wandering the streets, women who saw men walk in flames, and an owl who shrieked midday in the marketplace. Cicero points out the obvious—something important is about to happen. Cassius also recognizes the importance of the omens around him, and is invigorated by it because he realizes that the omens point to the end of Caesar's power, although he notes that the Senate has decided to make Caesar king the next day. It is this resolution that leads Casca to agree to join the conspiracy to kill Caesar before he can be crowned, and Cassius notes that there are several other senators ready to assist in the murder. However, despite the number of "honorable" senators involved in the scheme, the conspirators all realize that Brutus' participation in the murder is vital. As Caesar's best friend and an honorable member of the Senate, Brutus legitimizes the murder because he has no personal or political reason to kill Caesar other than his love for Rome. Cassius continues to manipulate this love by sending Brutus several notes from "citizens" urging Brutus to action.

Scene i: The complication in Act II begins with Brutus, who begins to receive the various notes left by Cassius. Brutus ponders Caesar's ambition, which is the main root of his fear that Caesar will become a tyrant. Although Brutus knows that his friend is extremely ambition, he has never seen anything that would indicate that Caesar might become tyrannical if crowned king. However, the mere thought of giving Caesar the opportunity to become a tyrant is enough to frighten Brutus into action. Brutus also notes that the only way to stop Caesar from becoming king is to kill him, and becomes resolved to do this upon reading the letters. Brutus also recalls the soothsayer's warning, and realizes that Caesar must be killed the next day (the ides of March) before he can be crowned.

When the conspirators arrive, Brutus immediately takes charge of the situation, despite his previous reticence about participating at all. It is Brutus who refuses to let the conspirators swear an oath to kill Caesar, and remind them that shaking hands should be enough to bind them together. Brutus also rejects involving Cicero in the conspiracy despite his good and wise reputation because he does not finish what he starts. Most importantly, Brutus rejects the notion of killing Antony, who Cassius notes is a "shrewd contriver" whose ambition may hurt the conspirators. Despite this, Brutus convinces Cassius to allow Antony to live because they will have killed too many people. Brutus also underestimates Antony in this scene, claiming that Antony is nothing more than a playboy puppet of Caesar. Cassius, of course, proves himself to be correct by the end of Act III—if Antony had been eliminated, the conspirators might well have succeeded in winning over the Roman public to their opinion. However, now that Brutus is committed to the conspiracy, he is the one who will make all of the decisions, whether or not they are accurate ones.

Another side of Brutus' character is revealed in his conversation with Portia. Portia is not the typical Roman wife—she is educated and beautiful, and has, until this point, shared a fairly equal relationship with her husband. Portia notices that Brutus is troubled as opposed to ill, and she begs him to reveal his thoughts to her. She wants to share in Brutus' troubles, but Brutus insists on protecting her from knowledge of the conspiracy. Although he loves his wife and promises to give her the explanation she seeks, Brutus has already separated himself from her by agreeing to kill Caesar. This separation is what eventually leads to Portia's death. By separating himself from his wife, Brutus once again demonstrates that he places his political duty above everything else and does not realize the ramifications of his decisions.

Scene ii: While the lightning storm continues, Caesar leaves his bedchamber to see who has come to visit him. Calphurnia, who has spent the night having nightmares of Caesar's death, begs him not to leave the house, especially considering that today is the ides of March. Despite the fact that "the heavens blaze forth the death of princes" and the numerous omens that have occurred during the night, Caesar insists on going to the Senate, stating that everything that has threatened him vanishes when he faces them, once again indicating his inflated opinion of his own power. Even when a messenger comes with news from the augurers that he should not leave his house because they could not find a heart within the beast that they sacrificed for a vision of the future, Caesar still insists on going to the Senate. It is only when Calphurnia begs on her knees that Caesar agrees to stay home. This action recalls the previous scene when Portia begs Brutus on her knees to tell her what is troubling him. Both men agree to do what their wives want but never actually follow through on it. In this case, Decius Brutus arrives and flatters Caesar into coming to the Senate House when Caesar reveals to him that Calphurnia has made him agree to stay home. Caesar tells Decius this because he does not want the senators to believe that he is too frightened by all of the omens to come. Decius then reinterprets Calphurnia's dream to a more agreeable end and then informs Caesar that the Senate has decided to make him king. Caesar's tremendous ego is far too large to resist Decius' flattering interpretation of the flowing statue, the idea that he might be called a coward for not coming to the Senate, and the coronation that is now emminent, which is why Caesar chooses to go to the Senate House.

Scenes iii-iv: These two scenes function to contribute to the rising action leading up to Caesar's death. In scene 3, Artemidorus reveals the conspiracy in a letter to Caesar, hoping to deliver it to him as he passes into the Senate House. In scene 4, Portia, who suspects that Brutus is plotting to kill Caesar, sends Lucius to his master to see what he is doing. Meanwhile, the soothsayer tells Portia that he, too, will be going to the Senate House to attempt to get Caesar to "befriend himself." Both scenes create tension because the entire plot of the play hinges on which party gets to Caesar alone first—the conspirators or those who conspire to protect Caesar.

Scene i: Although the conspirators escort Caesar to the Senate House, both Artemidorus and the soothsayer are able to speak with Caesar prior to his entry into the Senate. Caesar brags that the ides of March have come (implying that there has been no major incident), but the soothsayer reminds him that the day has not yet passed. Despite this, the warning is ignored. Artemidorus fares no better—when he gives Caesar the letter informing him of the conspiracy, Caesar chooses to read the one from Trebonius first, stating that what concerns him personally will be the last issue to be addressed. Although both of these warnings worry Casca, who fears the conspiracy has been discovered, they do not touch Caesar at all because Caesar refuses to see what the conspirators are capable of.

The murder of Caesar is couched in an appeal to Caesar. Metellus Cimber begs that his brother, Publius Cimber, be allowed to return to Rome as an enfranchised citizen. Caesar refuses, stating that while lesser men can be flexible, he must be "constant." He also tells the conspirators that he does not want anyone kneeling before him because he does not want that kind of flattery. Despite this, the conspirators all kneel, and because Caesar refuses to repeal Publius Cimber's banishment, Casca begins the murder. Although all of the conspirators stab Caesar, Shakespeare implies that it is Brutus who actually kills him: "Et tu, Brute?—Then fall, Caesar" (l. 85). Indeed, it is Brutus who has given legitimacy to this plot, and the conspirators may not have carried it out without him. He is also the one who has taken charge of the conspiracy even though he did not originally want to participate in it. Because of this, the idea that Brutus is the one who actually kills Caesar is at least figuratively correct.

Although the conspirators are successful in stopping Caesar from becoming king, they have little idea of how to proceed next, which is evident in their dealings with Antony and the Roman public. Antony, who chooses to flatter Brutus so that he will survive to avenge Caesar, shakes hands with the conspirators, indicating that he will agree to their plans. Cassius, however, is once again suspicious of Antony, and attempts to bribe him with thoughts of power, but this offer is ineffective. Brutus, too moved by the murder that has just occurred and too anxious to justify his actions, tells Antony that there are reasons for Caesar's death and that Antony can speak at Caesar's funeral if he agrees not to speak against the conspirators (although censorship is certainly not a part of the freedom and liberty that the conspirators claim they have provided to Rome). Cassius, of course, turns out to be correct in his assessment of Antony—Antony intends to avenge Caesar whether he is foresworn or not.

Scene ii: The people of Rome have heard the news of Caesar's death by this point and insist on an immediate explanation. The crowd, as suggested in Act I, scene 1 by their support of Caesar over Pompey, is easily swayed. They at first yield to Brutus' "logical" explanation for why the conspirators killed Caesar. Brutus claims that he killed Caesar because of Caesar's ambition, which would have resulted in the enslavement of the "free" citizens of Rome. He then points out that the only people who should be offended by Caesar's death are those who want to be slaves. Brutus claims that the death of Caesar is necessary for the benefit of Rome and that, should the time come that he is a detriment to his country, he should be put to death as well. The irony here is that Brutus' actions have resulted in the death of a caesar and the beginning of a civil war, and, as such, have been a great harm to the empire. The public, fickle as always, accepts Brutus' arguments and demand to make him Caesar. Then, in an attempt to be fair and to "render unto Caesar," Brutus persuades the crowds to listen to Antony's funeral oration. It is by doing this that Brutus makes one of his most fatal errors in the execution of the conspiracy.

When Antony speaks, the crowd does not want to listen initially. What changes their minds is the method in which Antony delivers his speech. Instead of trying to convince the public to feel sorry for Caesar, Antony uses reverse psychology by stating that he will not praise him. He then proceeds to mention all of the good Caesar has done, from being a good friend to bringing in money and slaves to helping the poor. While doing this, Antony uses the statement "Brutus says he was ambitious, and Brutus is an honorable man" at first to calm the crowd and later to remind them of the hypocrisy of the conspirators. Antony also uses Caesar's manipulation techniques, including dramatic pauses and crocodile tears, to change the crowd's opinion. He also gives the public time to consider what he says. What finally motivates the crowd is their own greed—when they discover that the will leaves money to all of the citizens and donates his property to the general public, their anger leads to rioting. Had Brutus stayed to hear Antony, he might have been able to prevent the crowd from turning against the conspirators. However, the conspirators are forced to flee the city, and Antony goes in search of Octavius, Caesar's heir, in order to decide on a plan of action.

Scene iii: This scene serves to further portray the violence and illogical nature of the Roman public. When Cinna the poet (as opposed to Cinna the conspirator) goes outside despite a warning in a dream that he should stay in, several citizens kill him despite the fact that they know he is not a conspirator simply because they are in a killing mood. After two other scenes highlighting the moods of the Roman public, it is not a surprise that they should do so. The masses turned on Pompey in favor of Caesar despite Pompey's tremendous popularity, they turned on Caesar in favor of Brutus after one speech, and they turned on the conspirators in favor of Antony and Caesaar after one more speech (and a "will"). They have also ransacked the city by this point. This is one of the major themes of the play—those who would have power must be able to ingratiate themselves with the masses. It is because Caesar and Antony are master politicians that they are able to succeed and overcome otherwise-popular figures like Pompey and Brutus. Those who cannot control popular opinion will end like Pompey and Brutus—destroyed by those more popular than they.

Scene i: The triumverate of Antony, Octavius, and Lepidus begin this scene much in the same way that the conspirators planned in Act II, scene 1. They make several decisions about who will live and who will die, citing reasons for each. They also attempt to extract money from Caesar's will, despite Antony's assurances in Act III, scene 2 that much of the money will go to the general public. Once Lepidus leaves, Octavius and Antony dispute his usefulness. Although Antony criticizes Lepidus as a horse that always needs direction, Octavius comes to his defense because he is a good soldier. Despite Octavius' young age, he is now Caesar, and he makes it clear in this scene that he will not be brushed aside by Antony despite Antony's greater breadth of experience. These tensions foreshadow the problems of Antony and Cleopatra.

Scene ii: This scene serves to counterpoint the situation in scene 1. Like the triumverate, the alliance between Brutus and Cassius does not appear to be as solid as it once was. Lucilius informs Brutus that Cassius does not treat him as well as he once did, indicating that Cassius is angry with Brutus. Indeed, when Cassius appears, he immediately accuses Brutus of wronging him, even though they are still in public. Brutus reminds him that they should speak privately, as a public disagreement is hardly constructive for an army that needs to maintain morale, and that they need to present a united front. They then move to Brutus' tent.

Scene iii: The argument continues in this scene. The accusations that fly back and forth between Brutus and Cassius underscore the tension of the failed conspiracy. Cassius, who killed Caesar out of jealousy and does not worry about being honorable, is angered by Brutus' morality even though this is the very attribute that made him so valuable to Cassius in the conspiracy plot. Brutus, on the other hand, is angered by Cassius' pragmatism, although this is what convinced Brutus to kill Caesar. The pressure to win this war is also affecting both men, who are on the run despite believing that they did what was best for their country. The friends do make up and find reasons for their ill humor—Cassius blames his mother, and Brutus tells Cassius that Portia has committed suicide.

The next section of the scene deals with military strategy. Although Cassius once again has the better idea by suggesting that they wait on attacking and make the forces of the triumverate find them, Brutus insists that they attack at Phillipi before Octavius and Antony are able to get more soldiers. Brutus' plan sounds logical, but like his speech in Act III, scene 2, and his refusal to kill Antony and Act II, scene 1, Brutus has overlooked the wisdom of Cassius. Cassius points out that it would be better to make Antony and Octavius seek them out because it will tire their forces while their own are able to rest and defend. When Cassius tries to make Brutus see his point, Brutus refuses to listen. Cassius once again agrees to Brutus' plan, even though he knows better than to do so. If Cassius' ideas had been followed throughout this play, the conspirators might well have controlled Rome. But because Brutus takes over as the head of the conspirators, the conspirators' plans fail.

This failure becomes evident to Brutus in the last section of the scene. The ghost of Caesar appears to Brutus, calling itself Brutus' "evil spirit." It then informs Brutus that he will see the ghost again at Phillipi, suggesting that Brutus will die. Brutus, just like Caesar and Cinna the poet, ignores the omen given to him. He knows he will see Caesar at Phillipi, as he indicates on line 330, but he chooses to do nothing to avoid it. The accuracy of the omens in this play suggests that there are signs that can predict the future but that people refuse to heed them.

Scene i: The discord in the conspirator camp during the last scene is once again paralleled by the disagreement between Octavius and Antony in this scene. Despite his lack of military experience, Octavius correctly predicts that the conspirators would attack at Phillipi, even though Antony thought they would not. Octavius also demands that he be the one to attack from the right side. When Antony asks why Octavius continues to question him, Octavius simply tells him that he is not crossing Antony, but will do as he pleases despite Antony's suggestions. It is clear from the opening part of this scene and the previous scene that no matter who eventually wins this battle, there will be no harmony in Rome.

Once the two sides have traded insults, Cassius and Brutus reveal more of their character in conversation with Messala and each other. Cassius notes that today is his birthday, and that he is being forced to fight a battle on this day against his will because of Brutus. It is at this point that Cassius reveals that he has begun to believe in omens, having seen the two eagles that had stayed with his legion fly away that very morning. However, Cassius has demonstrated belief in omens before. On the night before Caesar's assassination, it is Cassius who is invigorated by the otherwise terrifying occurrences because they signified Caesar's downfall. He believed this at the time despite claiming to be a believer in the teachings of Epicurus, who denied the existence of the supernatural. Because Cassius disagrees with Brutus' strategy in attacking at Phillipi and because he is beginning to believe in omens, Cassius makes his pact with Brutus to ensure that neither one of them will ever be taken prisoner.

Scene ii: In Scene 2, Brutus sees a weakness in Octavius' forces. Brutus' assessment of the situation is correct, but he leaves Cassius' army to the mercy of Antony. While the battle is balanced, this action eventually proves to be another miscalculation that leads to Brutus' downfall.

Scene iii: The results of Brutus' action in scene 2 manifest themselves in this scene, where Cassius' army is about to be overcome by Antony's forces. When Cassius sends Titinus to see if Brutus has been successful, his servant mistakes Titinus for a soldier that is taken prisoner. Not waiting for word to come from the camp, Cassius, once again believing in bad omens, decides to have his slave Pindarus kill him. Titinus blames this on a "lack of trust," which has created the destructive situation. This lack of trust, which is also evident between Octavius and Antony, will continue to plague Rome after the battle.

Brutus' reaction to Cassius' death demonstrates that he has not progressed in his understanding of warfare or the situation at hand. When he sees Cassius' body, Brutus' first inclination is to blame Caesar: "O Julius Caesar, thou art mighty yet;/Thy spirit walks abroad and turns our swords/In our own proper entrails" (ll.105-107). Given the omens, especially the appearance of Caesar's ghost, as well as the expert military advice of Cassius, Brutus should have known not to attack at Phillipi. Instead of taking responsibility for that decision, Brutus blames the power of Caesar, and instead of learning from his military mistakes, he orders a second attack.

Scene iv: In this scene, Antony demonstrates that despite being portrayed as a playboy and a betrayer, he still does have some honor. When Lucilius pretends to be Brutus in order to protect him, Antony orders that he be kept safe and given "all kindness." Antony orders this because he sees the worth of Lucilius and knows that he deserves to be treated with honor. Antony will demonstrate this again in scene 5 in his description of Brutus.

Scene v: The final scene of the play begins with Brutus in defeat. He begs several of his friends to help him kill himself, but their love for him is so strong that they cannot bring themselves to do so. This is because, as Brutus notes, he has never in his life found anyone that has betrayed him. This is ironic in that although Brutus loved Caesar, Brutus betrayed Caesar out of good for his country. Brutus' final lines, "Caesar, now be still./I killed not thee with half so good a will," imply that he was more hesitant to kill Caesar in than he is himself now. The honor that Antony shows in scene 4 is evident again in this scene, as is the respect of Octavius. When Octavius and Antony discover that Brutus has committed suicide by his own sword rather than be taken prisoner (which was considered an honorable way to die by the Romans), both Octavius and Antony are respectful of his servants and of him. Octavius takes Strato as a servant, and Antony gives Brutus a short but important eulogy, noting that Brutus, not Caesar, was "the noblest Roman of them all" (l. 74). Not to be outdone, Octavius orders a proper burial for Brutus, even though Roman military code did not require proper burial of an enemy. Octavius even orders that Brutus' body lie in his own tent, a type of "lying in state" not usually accorded to traitors. However, despite the solemnity of the moment, Octavius is still determined to celebrate the "glories of this happy day," even though all of the repercussions of this event have yet to unfold (Shakespeare leaves that part of the story to Antony and Cleopatra).