These are the circumstances at the beginning of the play. At first, it seems like this us just another "Thebes has a problem, Oedipus makes it go away," deal.
Oedipus struggles to get Teiresias, the messenger, and the shepherd to talk. He’s desperate to solve the mystery but he keeps being urged to drop it.
The more Oedipus learns, the more he wants to know. Although he is inching closer to the truth, he is damaging himself in the process.
In a moment of horror, Oedipus understands what he’s done. This is the emotional and psychological climax of the play.
Oedipus sees that Jocasta, too, has realized what they’ve done. The suspense is inherent in the fact that we don’t know if Oedipus, too, will kill himself. Given that this is a Greek tragedy, we’re a little bit scared that everyone involved will suddenly commit suicide as well. It’s quite suspenseful.
With complete knowledge of what he’s done, Oedipus inflicts injury on himself and begs to be exiled from Thebes.
In the last moments of the play, Oedipus is banished from his home.