The protagonist of the story is the son of royalty in Thebes. Before the story even begins, the audience knows that King Laius has been murdered on his way to consult an oracle in Delphi. In addition, it is known that Oedipus has been proclaimed as king of Thebes after he solves the riddle of the terrorizing Sphinx. The information that we are given allows for dramatic irony throughout the story; we know vital information that is unknown by the characters of the play.
After a prophecy is revealed about Oedipus's fate, Jocasta recants a story about how she was told that her son was going to kill his father and sleep with his mother which she assumes never came true. As the story progresses, Oedipus, curious about his past and true origins, invites a shepherd to tell the story of his youth.
Oedipus learns that the shepherd was given Oedipus as a boy and took him back to Corinth to the king and queen to be raised as royalty proving that the royalty of Corinth were not his biological parents. Oedipus learns that after he ran away from Corinth, he met his biological father, King Laius, who he killed after an argument. Next, he became king after solving the sphinx's riddle and married his mother, who was Laius’s wife. Jocasta, overridden with emotion, hangs herself, and Oedipus gouges out his own eyes with pins from her dress.
Oedipus’s Limit of Free Will
Ultimately, Oedipus succumbs to a foretold prophecy. The prophecy that is presented is fulfilled, and aims to justify the power and ultimatum of the gods. The fulfillment of the prophecy that is given to Oedipus regarding the death of his father and the incest with his mother shows that humans are relatively powerless before the gods and corroborates the notion that humility is an essential element to a successful life. After Oedipus learns of the prophecy from Tiresias, he tells Jocasta of a prophecy that he heard years ago. Jocasta then informs Oedipus that she was told a similar prophecy and debates that prophecies should not be trusted in general because she assumes the one that she was told did not come true.
On the contrary, It is difficult not to acknowledge that Oedipus had no influence on the prophecy; the end of the tunnel seemed to be inevitable for him. He is sent to Corinth as a baby and is raised in royalty. When he hears of the prophecy from a drunk man, he runs away to avoid killing the man he thinks is his father, the king of Corinth, to end up killing his biological father, King Laius.
The Irony of Sight
There are numerous references to sight and blindness throughout the story. While, Oedipus is famed for his clear sight and impeccable discretion, he discovers that he is metaphorically blind for the majority of his rule because he is unaware of his true origins. After discovering that he had been “blind” for so long, he gouges out his eyes so that he will never have to look (another reference to sight) at his own children again.
It is quite ironic that the aged prophet, Tiresias, is physically blind, however, he comprehends and "sees" more than others who physically have sight. The play illustrates that despite intelligence and knowledge, most humans have very little control over their destiny, thus are "blind."