The Narrator sets the scene, and comments on the action throughout the opera in the language of the audience. Of Oedipus, king of Thebes, he says: “At the moment of his birth a snare was laid for him – you will see the snare closing.”

The men of Thebes lament the plague which is destroying the people of the city, and they petition their king to help them, which he promises to do. Creon, whose sister Jocasta is Oedipus’ wife, enters from Delphi, where he has consulted the oracle. He announces that the late King Laius’ murderer still lives in Thebes unpunished, and this has caused the Gods to send the plague. Oedipus promises that he will find the murderer. He sends for Tiresias, the blind soothsayer, for help.

Tiresias, ‘the fountain of truth’ is strangely reluctant to answer the King’s questions. Taunted by Oedipus, however, the old man promises to tell everything: King Laius’ assassin is himself a king! Furious at the implication of these words, Oedipus accuses Creon and Tiresias of conspiring to oust him from the throne.

Attracted by the quarrel, Jocasta enters to warn her husband and her brother against raising their voices in the plague-stricken city. Oracles, she says, often deceive: did not an oracle predict that her former husband, Laius, would be killed by his own son, when, in fact, he was killed by robbers at the crossroads between Daulia and Delphi? Hearing this, Oedipus is filled with horror. He tells Jocasta that he killed a stranger at this very crossroads.

A messenger brings the news that King Polybus, who raised Oedipus, is dead, and that it has been revealed that Polybus was not Oedipus’ father, but had found him abandoned as a baby on a mountain slope. The shepherd who found Oedipus corroborates this news. Overwhelmed, Jocasta goes into the palace. The messenger and shepherd with the chorus accuse the King of the double crime of parricide and incest. Faced with the evidence, Oedipus, with quiet dignity, admits that this must be the truth. Bowed with his guilt, he leaves.

The messenger reappears to tell the fate of the stricken pair: Jocasta has hanged herself, and Oedipus has pierced his eyeballs with the golden pin she wore. As the chorus mourns Jocasta’s fate, the broken Oedipus reappears, and chorus gently bids the sightless man a last farewell.