A priest and the chorus of Thebans arrive at the palace to call upon their King, Oedipus, to aid them with the plague. Oedipus had sent his brother-in-law Creon to ask help of the oracle at Delphi, and he returns at that moment. Creon says the plague is the result of religious pollution, caused because the murderer of their former King, Laius, had never been caught. Oedipus vows to find the murderer and curses him for the plague that he has caused.
Oedipus summons the blind prophet Tiresias for help. When Tiresias arrives he claims to know the answers to Oedipus’s questions, but refuses to speak, instead telling Oedipus to abandon his search. Oedipus is enraged by Tiresias’ refusal, and says the prophet must be complicit in the murder. Outraged, Tiresias tells the king that Oedipus himself is the murderer. Oedipus cannot see how this could be, and concludes that the prophet must have been paid off by Creon in an attempt to undermine him. The two argue vehemently and eventually Tiresias leaves, muttering darkly that when the murderer is discovered he shall be a native citizen of Thebes; brother and father to his own children; and son and husband to his own mother.