As the title of Sophocles' play implies, the focal point of this tragedy is Oedipus, who was the son of Laius and Jocasta. The play mentions how Oedipus was left to die when he was a baby, rescued by a Theban shepherd, transferred to the possession of a Corinthian shepherd, and then finally was given to Polybus and Merope, the king and queen of Corinth.
Sophocles' play tells how Oedipus, as a young man, began to suspect that he was not the natural child of Polybus and Merope, and how he went to the oracle at Delphi to ask the god about this matter. Receiving the horrific answer that he would kill his father and marry his mother, Oedipus decided never to return to Corinth.
On the way from Delphi, Oedipus gets into a violent altercation with his real father Laius (neither father nor son recognize the other) and Oedipus kills Laius. Oedipus continues on his way and ends up in Thebes. Sophocles' play mentions that Oedipus solved the riddle of the Sphinx, who was tormenting the Thebans, and in this way Oedipus became the savior of the town, their new king, and also the husband of the Theban queen, Jocasta.
Sophocles' play opens after an unspecified number of years have passed (long enough for Oedipus to have fathered four children by Jocasta). As the play opens, the Thebans are in the midst of a horrible plague, which they call upon Oedipus to remedy. Oedipus discovers that the plague will end if the city drives out the killer of Laius. Oedipus promises to his best to do so, but in the course of his investigation, he discovers that he himself killed Laius.
At the play's end, Oedipus is removed as king, separated from his children, and sent into exile. Thus, the major focus of Sophocles' play is on the fate of Oedipus. Of course, the play has many other characters, but what happens to Creon, Teiresias, and Oedipus' children is not discussed in the play. Jocasta kills herself near the end of the play, but her fate is not the focal point of the play.
As the play ends, the Chorus' parting words have Oedipus as their focus:
"You residents of Thebes, our native land,
look on this man, this Oedipus, the one
who understood that celebrated riddle.
He was the most powerful of men.
All citizens who witnessed this man’s wealth
were envious. Now what a surging tide
of terrible disaster sweeps around him."
(Ian Johnston translation)