Oedipus insists that Creon must die for organizing the conspiracy. Creon is still loudly protesting his innocence when Jocasta arrives. She's the link between them: Creon's sister and Oedipus' wife. Her intervention makes Oedipus back down, and Creon is allowed to go, his fate unclear, still muttering about the injustice.
Oedipus is now alone with Jocasta, and reveals his worries. He says how Creon, using Tiresias the prophet as his front man, was plotting against him. Jocasta says all prophecy is bunk - and tells the story of her son to prove it. Laius, according to Apollo's prophets, was supposed to be killed by his son: but he was killed, poor man, by strangers at the a place where three roads meet, a crossroads. The baby died, exposed with his ankles skewered, on Mount Cithaeron.
But something about this story worries Oedipus - why? Does he think ...

• ...he may have killed his father?
• ...he may have killed Laius?
• ...Jocasta may be his mother?