Agamemnon, the first play of the Oresteia trilogy begins much like other great plays, such as Hamlet, on the walls of the city with a a lone watchman who bemoans the state of affairs, waiting for a light showing that Agamemnon, his king, is returning home from the Trojan War. Upon spotting the foreboding beacon, he scrambles to tell Clytemnestra of the news, which she doubts. As Aeschylus’s play represents the culmination of Greek lyric poetry synthesized with Greek theatre, and multiple players on stage, the play features a notable struggle between the Greek elders, the Chorus, and Clytemnestra. A lone herald comes forth first announcing Agamemnon’s return, followed by Agamemnon himself, who appears not in disguise, apparently learning nothing from his great and notable comrade, Odysseus. Instead, he follows in the short-sighted footsteps of Achilles. As a result, Agamemnon carries with him a curse that befalls him for the murder of his daughter Iphigenaia, for which his wife, Clytemnestra, has never forgiven him. Additionally, he brings home a cocubine from Troy, Cassandra, that enrages Clytemnestra. However, his family’s curse goes back much further to the feud between Agamemnon’s father, Atreus and his twin brother Thyestes, and some would say, even further to the curse of Tantalus, the Titan. Atreus murdered his brother’s children and fed them to him for committing adultery and sleeping with Atreus’s wife -successive generations of his family are thus cursed in their efforts. This culminates in Agamemnon’s murder by Clytemnestra, however in other accounts it is her lover, Aegisthus who commits the murder.
In the second part of the play, The Libation Bearers, Orestes returns from mainland Greece to find his sister pouring libations on the grave of their father. Together, they devise a plan to exact revenge on their mother and her imposter suitor. Orestes appears at the palace doors as a wandering traveler who announces the death of Orestes. Offstage, he kills Aegisthus and exposes his identity to his mother, before killing her, too. After this bloody affair, he flees the palace as the furies, or Eumenides, haunt him and chase him away.
The final part of the play, The Eumenides, at least what has survived for the modern eye, begins at the Pythia who beckons Apollo and it opens with a dialogue between Apollo and the Chorus of furies. The ghost of Clytemnestra appears to the sleeping furies, who have been put to sleep by Apollo, and she scolds them for not doing their duty to exact revenge. The scene is set when Athena appears and conducts a trial over whether to accuse Orestes of the crime of matricide or to find him blameless. Apollo comes to his defense and the furies are given a new role, underground, while Athena warns the Athenians to maintain a sense of fear, while also self-governing themselves, and to always hold themselves upright for having overcome the barbaric cycle of vengeance and retribution.