Familial betrayal is the name of the game in Electra. A father sacrifices his daughter to the gods, a wife kills her husband, a daughter conspires to kill her mother, and a son commits matricide. The play takes a look at "blood for blood" reasoning as the cause of a long line of one betrayal after another and questions the wisdom of such a vengeance-driven justice system.
By failing to inform Electra ahead of time of his plan, Orestes betrays his sister.
By failing to condemn the actions of the royal couple, Clytemnestra and Aegisthus, Chrysothemis betrays her father.