The play begins with Oedipus, king of Thebes, offering to do whatever it takes to release his fellow citizens from the plague that besets the city. A priest tells him that they need his help: after all, many years earlier, Oedipus freed the city from the Sphinx, so he is known to be good at solving problems. Oedipus is way ahead of them: he has already sent his wife’s brother, Creon, to Delphi to ask the Oracle for advice. He’s barely finished explaining this when Creon appears onstage with the news that Thebes is polluted with the plague because it is harbouring the murderer of the previous ruler, King Laius. Oedipus asks where Laius died. On his way to Delphi, is the answer. Set upon by thieves and killed. Why didn’t you hunt down his killers at the time? asks Oedipus. The Sphinx told us to leave it, his brother-in-law replies. Right, says Oedipus, I’ll solve the crime, even though I wasn’t here then.
Tiresias, the blind seer, enters and tells Oedipus to leave well alone, implying that he – Oedipus – is himself the man he seeks, the killer of Laius. Oedipus is livid: are you conspiring with Creon, he asks, so he can be king? Remember how I solved the Sphinx’s riddle? Do you really want to try and overthrow me? Tiresias warns him that he will regret his words and leaves, muttering the terrible truth about Oedipus’ parentage. Oedipus and Creon then also argue, the latter being understandably peeved to find that he has been accused of treason. It was your idea to ask Tiresias for help, Oedipus replies. And now he says I’m the killer. Which I’m not, because I wasn’t even here then, so you must be conspiring with one another. No, Creon replies. I don’t want to be king. I have plenty of power as your brother-in-law, thanks.
And then, at last, almost halfway through the play, Jocasta enters. She intervenes between her husband – Oedipus – and her brother – Creon, telling Oedipus that he is wrong to suspect Creon. Fine, says Oedipus. He’ll probably destroy me, but by all means let him go. Why are you so angry? Jocasta asks. Tiresias says I killed your first husband, Laius, Oedipus says. What do prophets know? she replies. An oracle told Laius he’d be killed by his own son and he wasn’t. He was killed by strangers, by bandits, at a place where three roads meet. And his son, our son, was exposed to death years earlier on the mountain when he was three days old.
Wait, Oedipus says. Did you say a place where three roads meet? What did he look like, Laius? He looked a bit like you, says Jocasta. Was he definitely attacked by bandits? Oedipus asks. Did someone say there was a survivor? Send for him. Jocasta wonders what he is frightened of. Well, Oedipus replies, you know I grew up in Corinth. A drunk man at a banquet once told me I was adopted. So I went to Delphi and asked the Oracle, and she told me that I would kill my father and have sex with my mother, and I’d produce incestuous offspring. To avoid this dreadful fate, I decided never to return to Corinth. And, on my way out of Delphi, I met a rude old man at a place where three roads meet and we argued and I killed him （he started it, by the way）。 I killed his men, too. And now I am afraid that it was Laius and he and I were related and I’ve done something terrible. But this witness we’ve sent for apparently said they were attacked by a group of men, in which case, that wasn’t me and it’s okay.
I remember the witness coming back to Thebes, Jocasta says. He definitely said ‘bandits’， not one bandit, don’t worry. And anyway, prophecies don’t mean anything3 – my son was killed as a baby before he could kill Laius, remember? That’s true, Oedipus says. But send for the man anyway. Jocasta leaves the stage, and when she returns, she prays to Apollo. It’s a bracing change of attitude, since – only moments ago – she was saying oracles were meaningless.
Suddenly a messenger arrives from Corinth to tell Oedipus that Polybus, the king of Corinth and the man Oedipus believes to be his father, is dead. Jocasta and Oedipus are delighted: if Polybus is dead, then Oedipus didn’t kill him. I said not to worry, says Jocasta. Everything’s down to chance. You didn’t kill your father and you won’t marry your mother. Loads of men dream of sleeping with their mothers – it means nothing.4 And at least you definitely didn’t kill your father.
But then the messenger reveals that Oedipus was indeed adopted. He had no need to avoid Corinth after all. The messenger gave Oedipus to Polybus and Merope when he – Oedipus – was just a baby, with his feet pinned together, hence his name: Oedipus, in Greek, means ‘swollen foot’。 Where did you get me? asks Oedipus, horrified. From a Theban shepherd, comes the answer. This turns out to be the very man who witnessed and survived the attack on Laius. Jocasta suddenly understands the truth, and begs Oedipus to stop pursuing the mystery of who killed Laius, and of who he is. He refuses to listen and she runs into the palace, saying the only name she has for him is ‘wretched’。5