A plague has overtaken Thebes, and Kreon has been told by an oracle that they must find the murderer of King Laios to stop it.
By exile or death, blood for blood. It was murder that brought the plague-wind on the city (Lines 104-105).
Scene 1
A blind seer named Teiresias is summoned to help solve the murder, and he claims Oedipus is the killer.
But I say that you, with both your eyes, are blind: you can not see the wretchedness of your own life, (Lines 196-197).
Scene 2
Oedipus accuses Kreon of conspiring against him, and they argue with each other.
Poor foolish men, what wicked din is this? (Line 128).
Iokaste tells Oedipus of the events of Laios's death, and Oedipus remembers a similar event and believes himself guilty. They summon the shepherd who witnessed it.
Scene 3
A messenger comes and tells them that Polybos, the king of Corinth, is dead. He also says that Oedipus is not actually Polybos son.
They learn that the very shepherd they are summoning is the one that found Oedipus and gave him to them.
No more your father than the man speaking to you (Line 103).
The shepherd arrives, and after some persuading, he reveals he was tasked to let Oedipus die.
Scene 4
But instead he gave him to the messenger. He says Oedipus is really Laios and Iokaste's son.
No man living is more wretched than Oedipus (Line 67).
Exodos
Iokaste kills herself, and Oedipus stabs his eyes out. He then imposes an exile on himself.
Let me purge my father's Thebes of the pollution of my living here, (Lines 223-224).