Oedipus leaves his palace to see priests giving offerings to the gods because Thebes has been struck by a plague. They tell him, and he says he feels bad, and has sent his brother, Creon, to Apollo's oracle to find out how to end the plague. Creon returns to say that to end the plague, the murder of Laius, the previous king, must be killed.
Oedipus brings in the blind prophet Tiresias to to tell him to Laius' killer is, but he will not say. Oedipus accuses Tiresias of the murder, and he begins to hint at who the real murder is. Oedipus insults Tiresias, but Tiresias simply says that Thebes will soon be insulting Oedipus. Oedipus starts ranting about how Tiresias and Creon are plotting to steal the throne.
As Oedipus and Creon argue, Jocasta tries to intervene. She assures Oedipus that he was not guilty of Laius' death. She says no one can predict the future. She tells the story of how Laius was killed, and Oedipus is frightened because he didn't know where Laius had been killed, and he thinks he may have been the one that killed Laius.
As a young man, someone told Oedipus that he was not the true son of his father. He is enraged by this, and asks his parents. They are also angry with the man, but Oedipus can't drop it. He goes to Apollo's oracle to get answers. He is told that he will kill his father, and marry his mother. On his way back, he runs into some men and they anger him, so he kills them.
A messenger then arrives from Corinth to tell Oedipus that his father, Polybus has died. Jocasta is happy because apparently his father died of natural causes, so the prophecy that Oedipus kills his father must not be true. The messenger then reveals that Polybus and Merope were not Oedipus' true parents, but Laius and Jocasta were.
The messenger enters to tell the Chorus that Jocasta has killed herself. She had locked herself in her room weeping for Laius and cursing Oedipus. Oedipus, extremely angry and in a frenzy, rushes into her room with a sword, and sees her dead. He runs to embrace her, and gouges out his eyes. Creon later enters and Oedipus asks to be banished.