Coriolanus chides his wife for her tears and his mother for her grief-stricken words as he is about to go into exile. He urges his mother to assume her stoic ways, and assures her that he himself will follow her example and thereby come out of the ordeal better than most others would given the same predicament. Unconsoled, Volumnia urges Cominius to stay with Coriolanus awhile and to arrange matters so that the dangers her son will be exposed to will be minimized. Cominius is more than eager to do what he can to mitigate Coriolanus’ exile, but Coriolanus tells Cominius that he needn’t bother, that the burdens Cominius has assumed in the wars has earned him much needed rest.
Having achieved their goal, to undo Coriolanus, Brutus and Sicinius have the Aedile dismiss the people, and they themselves skulk away, determined to avoid confronting Volumnia who, in the company of Virgilia and Manenius, is espied approaching them. To the tribunals’ chagrin, Volumnia accosts them and then upbraids them for having discredited a man better than themselves. Having had her say, Volumnia suffers them to leave and confides in Virgilia and Menenius, saying how her life would be somewhat more bearable if she had the opportunity to upbraid the tribunes daily.
Nicanor, a Roman who is allied to the Volscians, recognizes Adrian, a Volsce who is presently on his way to Rome to seek out Nicanor. At first, Adrian doesn’t recognize Nicanor, but when he eventually does, Nicanor apprises Adrian of the good news: Coriolanus has been banished and the Romans are at odds with one another, making them vulnerable to a Volscian surprise attack. The news, in addition to the fact that their accidental meeting has saved him extra labor, greatly pleases Adrian, and by and by he and Nicanor set off for the Volscian territories to apprise the Volscian command of the situation in Rome.
Muffled and disguised in rags, Coriolanus enters Antium, the city wherein dwells his inveterate enemy Tullus Aufidius. Having decided to solicit Aufidius’ patronage for better or worse, Coriolanus asks and is directed to Aufidius’ abode by a citizen of the city.
Coriolanus has stationed himself inside Aufidius’ house which is presently in a state of great activity on account of a banquet that is being held in honor of the Volscian nobles. Three of Aufidius’ servants spot Coriolanus loitering, but they each fail to drive him out. One of servants fetches Aufidius who proceeds to interrogate the loitering stranger. At first, thinking Aufidius would eventually recognize him, Coriolanus is reluctant to disclose his identity, much less his purpose. Aufidius doesn’t recognize Coriolanus, however, compelling Coriolanus to reveal that he is Caius Marcius; that he would like nothing better than to exact revenge on his nation who have ungratefully and foolishly exiled him; but that he would be more than willing to die if Aufidius decides to kill Coriolanus here and now. However, to Coriolanus’ vindictive satisfaction, Aufidius embraces his inveterate enemy as a new ally and welcomes Coriolanus to join him in opposing his former countrymen. Thus resolved, Coriolanus is taken to be greeted and introduced to the Volcian nobles. Meanwhile, Aufidius’ servingmen gossip about the incredible turn of events.
Brutus and Sicinius are feeling good about themselves when their ease is disturbed by the news of a Volscian attack which is being led by Tullus Aufidius who is allied with, of all people, Caius Marcius. The legitimacy of the news is questioned even doubted to the extent that the tribunes order the gossipmonger, who is creating citizen unrest, to be whipped and silenced only to be persuaded by Cominius that the news isn’t gossip but confirmed fact. Subsequently, Cominius and Menenius argue that it serves the tribunes and the Roman citizens right to have their vindictive decree fall on the inventors’ heads, so to speak. True to his fickle nature, each citizen disavows that in his heart of heart he had approved of Caius Marcius’ banishment. As to the tribunes, they put on their best faces, insisting to the end that the news is mere gossip and betraying their true feelings, which is mortification at the thought of Caius Marcius coming for their hide as a Volscian ally, only to one another.
Report of Caius Marcius’ astounding success, on the battlefield, prompts a Volscian lieutenant to admit that he—the lieutenant—would’ve preferred if Aufidius had undertaken the attack of Rome all by himself or if he let Caius Marcius do it all by himself. In any event, the lieutenant tells Aufidius to be wary of Marcius whose exploits are gaining him more renown than Aufidius himself could ever hope to gain for himself. Caius Marcius' growing renown notwithstanding, Aufidius tells the lieutenant that he really can’t hold any grudge towards Marcius as Marcius is only doing what he has promised to do, assuring the lieutenant that if or when Marcius brings Rome to its knees, then that is when Aufidius will have the upper hand of Caius Marcius, which he has been seeking for all his life.