What conflict or problem do the people of Thebes face as play opens?

As the play Oedipus Rex opens, the city of Thebes is facing a severe plague that has caused many deaths and plunged the city into despair. The people are suffering from various illnesses, crops have failed, and the city is in chaos. The citizens of Thebes believe the plague is a punishment from the gods, and they plead with Oedipus, their king, to find a solution and save the city from the crisis.