On account of Cominius’ failed attempt to persuade Caius Marcius to take mercy on Rome, Menenius is reluctant to go and speak with Caius Marcius when the tribunes insist that he at least try, that if he try and fail that Rome will be grateful all the same. Menenius decides to try, and to increase the likelihood of success he determines to go after Marcius has supped, arguing that men are more apt to be kind and reasonable on a full stomach than on an empty one. Meanwhile, Cominius, who doubts that Menenius will be any more successful than he and who believes that Rome’s only hope lies with Marcius’ mother and wife, prevails upon the tribunes to go with him and beg Volumnia and Virgilia to do what they themselves—Cominius and the tribunes—are powerless to do: convince Marcius to spare Rome.
When two Volscian guards deny his request to see their new general Caius Marcius, Menenius protests, citing his reputation—he has been Caius Marcius’ number one advocate—which ought to give him special dispensation. The guards argue, however, that in light of Rome’s disgraceful treatment of her own savior, it would take something far more than an old man’s entreaty to appease Marcius’ fury. By and by, Menenius’ wish is granted when Caius Marcius, who is accompanied by Aufidius, passes by, noting Menenius. Menenius greets Marcius as if they were father and son, but Marcius dismisses the old man, arguing that even his mother, wife, and child are now nothing to him. However, on account of their old friendship, Marcius gives Menenius a letter and then departs with Aufidius. Feeling vindicated, the guards gloat, but Menenius dismisses them, assuring them that as he has no fear of dying he has no fear of dying of Marcius’ wrath.
Caius Marcius assures Aufidius that he will be true to his promise and lay Rome to waste, and that he will no longer receive any petitioners from his former countrymen even if they are family or close friends only to behold his mother, his wife, his wife’s friend Valeria, and his son who have come to petition him. Thoroughly out of sorts, Marcius can’t help but to kneel before his mother who in turn kneels before her son. Nonetheless, Marcius makes it plain that he cannot grant her her wish, i.e. spare Rome by withdrawing his Volscian army. Volumnia assures her son that she doesn’t expect him to betray his cause, but that in light of the impossible situation that Marcius has put his family in that the least he could do is listen. Marcius listens and is so taken by his mother’s speech—which is a request that Marcius have the Volscians grant the Romans mercy lest Marcius proceeds and levels his former country to rubbles, making his name forever synonymous to that which is cruel and unnatural—that Marcius relents and decides to do as his mother advises. When Marcius turns to Aufidius, the latter ostensibly assures the former that he understands, that he would do the same were their places switched.
Menenius is upbraiding Sicinius for what he and Brutus have done when a messenger warns Sicinius to run and hide what with Brutus being held hostage by a Roman mob who promise Brutus a slow, lingering death if Marcius’ family’s petition fail to secure Rome her salvation. Luckily for Sicinius, another messenger arrives but this time to deliver great news: Volumnia,Virgilia, and Valeria have succeeded where Cominius and Menenius have failed. Rome will sue for peace, and the Volscians will grant it.
As Volumnia, Virgilia, and Valeria return to Rome, a senator directs the ceremonies honoring the three ladies who have saved Rome.
Tullus Aufidius dispatches a letter in which he informs the Volscian lords of his arrival in the city and in which he prepares them for the extreme measure he is about to take with regards Caius Marcius. Presently, he shares a word with his conspirators who are more than willing to do their part and who wonder if Aufidius is as eager to go through with the plan as they are. Aufidius confirms that he is as eager, citing that the peace treaty that Caius Marcius has taken upon himself to negotiate on behalf of the Volscians amounts to treason. By and by, the Volscian lords arrive, and they agree that Caius Marcius had no authority to negotiate a peace treaty. It isn’t long when Caius Marcius arrives to great adulation as, en mass, the Volscian citizens follow Caius Marcius (another stick in Aufidius’ craw). Presently Aufidius impeaches Marcius, accusing him of treason. Aufidius avers that Marcius had no right to suspend his attack on Rome. He then insults Marcius who can’t help himself but to brag of his exploits at Corioli to counter Aufidius’ claim that Marcius has no right to call himself Coriolanus. It’s a calculated move by Aufidius to build a pretext to assassinate Coriolanus. Indeed the Volscian people, reminded of Coriolanus’ exploits at Corioli where their family and friends were slaughtered, demand that Coriolanus be killed. Aufidius’ conspirators oblige and kill Coriolanus. The Volscian lords object, arguing that Coriolanus, being noble, did not deserve such a barbaric end. A moment’s reprieve saddens Aufidius. He orders that Coriolanus be given full honors in the rites of death.