Jocasta is a conflicted character who appears doomed from the start. This doom begins in a prophecy; that is, that Laius will die by his son's (Oedipus) hands and sleep with his mother, Jocasta.
As life progresses, Laius is murdered and Oedipus and Jocasta wed, having four children: Antigone, Polyneices, Eteocles, and Ismene. However, both are unaware of their blood relationship. Interestingly enough, Jocasta plays a complicated role in this play, that of both spouse and mother. This role foreshadows her fate upon discovery that Oedipus is actually her son, the child she thought dead on the mountainside so that the terrible prediction would be avoided.
Oedipus is determined to discover who killed Laius, and then the plot unravels, as he wants to uncover an uncomfortable truth about his identity. Ultimately, Jocasta has no escape but suicide when she discovers she has committed incest. Her despair concerning her actions is inconsolable. Ultimately, she is a strong, sympathetic character.