Plot Summary: Agamemnon, King of Sparta is betrayed and killed by his wife Clytemnestra after returning from the Trojan War. Clytemnestra marries Aegisthus and both are afraid of retribution from Agamemnons son and daughter. The son, Orestes, is removed from Sparta by a tutor loyal to Aga. before his new stepdad has a chance to kill him. The daughter, Electra, is married off to a peasant to try and prevent her from begetting heirs strong enough to avenge Agamemnon. Play opens. Orestes returns to sister from exile, they plan to take revenge. They find the tutor, who tells them Aegisthus is in a nearby field. Orestes goes and kills Aegisthus. They invite Clytemnestra to Electras house on the pretence of her having given birth. Once there, they kill her. Then, the demigod Castor appears to them and denounces them on account of committing matricide. They are forced into shameful exile. Play ends.
Given how dramatic this sounds there is really very little drama or tension in the play. The characters tell us what they are about to do, go and do it, (often off screen) and then come back and tell us how they did it.