In Oedipus Rex, the action of the play begins with the people asking Oedipus for help. There is a plague on the land. When Oedipus inquires about what could be causing the plague, he learns that the murderer of King Laius must be punished. Without knowing that he himself is the murderer, Oedipus seeks to find the information on the murderer.

When the blind prophet Teiresias will not tell what he knows, Oedipus accuses Teiresias of being involved in the murder somehow. In anger, Teiresias informs Oedipus that he is the murderer:

After much pleading and mutual antagonism, Oedipus makes Teiresias say what he knows: that it was Oedipus who killed Laius. Outraged at the accusations Oedipus calls him a "fortuneteller" and a "deceitful beggar-priest." 

Unfortunately, Oedipus had indeed killed King Laius years ago, not realizing King Laius was his father. A shepherd reveals the truth:

 The shepherd enters and tells Oedipus, after a great deal of resistance, that he is Laius's son and that he had had him taken away to his own country by the messenger so as to avoid his fate. The chorus bewails the change in Oedipus from revered and fortunate ruler to one who has plunged into the depths of wretchedness.

Now, Oedipus is married to his mother. He has children by his own mother. As the story progresses, Oedipus learns the truth. Jocasta, his mother, hangs herself upon learning the truth and Oedipus blinds himself with Jocasta's brooches:

 A second messenger reports that Jocasta has just committed suicide, having realized that she was married to her son and thus had given birth to his children. He also reports that the king, suffering intensely upon hearing the news of his identity, blinded himself with the Queen's brooches. Oedipus has also requested that he be shown to the people of Thebes and then exiled; he comes out, bewildered and crying, asking for shelter from his painful memory, which cannot be removed as easily his eyes could be.