Menenius tries to calm a mutiny among the Roman citizens over the way they have been treated by the nobles. His friend Caius Martius treats them with contempt, and the citizens disperse. Martius' attitude arouses the anger of the tribunes Sicinius and Brutus.
News arrives that the Volsces are in arms under Aufidius, who has been sent to attack Rome. Volumnia and Virgilia proudly discuss Martius' earlier feats, and are visited by Valeria, who reports Martius' arrival at the Volscian city of Corioles.
The generals Comenius and Titus Lartius attack. Martius plays a major role in several skirmishes, and there is a fight between him and Aufidius, after which Corioles is captured. For his part in the battle, Martius is given the honorary title of Coriolanus. Coriolanus returns to Rome, where he meets his family and finds himself nominated for a consulship.
For the nomination to be valid, he needs to present himself humbly to the people and obtain their votes, a task which he carries out grudgingly. The people do give him their votes, but Brutus and Sicinius then portray him as the people's enemy, and they change their minds. When this is reported to Coriolanus, he cannot contain his anger; he speaks out against the people, and is accused of being a traitor.
A violent confrontation forces him to leave. After being advised by his family and friends, he returns to meet the people, intending to speak mildly, but is unable to control himself at their taunts, and is banished. Volumnia delivers some harsh words to the tribunes.
The Volscians, meanwhile, have taken up arms again. Coriolanus goes to offer his services to Aufidius, and is made welcome. When the news of this alliance reaches Rome, there is panic, and the people begin to regret what they have done. They send supplicants to ask Coriolanus to spare Rome. He rejects the approaches of Cominius and Menenius, but eventually yields to Volumnia, Virgilia, Valeria, and Young Martius, who are received back in Rome with great joy.
Meanwhile, the popularity of Coriolanus grows among the Volscians, much to Aufidius' dismay. He meets with a group of conspirators, and when Coriolanus returns he is once again called a traitor, and killed.
Aufidius immediately regrets his actions, and the Volscians prepare to give him a noble funeral.