For years Electra has mourned her father and openly spurned her mother and stepfather for murdering him. She spends her time crying, wailing, and openly casting accusations at them. Her father, Agamemnon, was murdered by Electra's now stepfather, Aegisthus, at the urging of her mother, Clytemnestra. Although she is a king's daughter, Electra dresses in ragged clothing to further show her disapproval of her mother and stepfather, who, she feels, treat her as a slave. Every day Electra expects her brother, Orestes, to return from exile and act upon their shared desire for revenge. When she learns that Orestes is dead, she tries to convince her sister Chrysothemis to help. Her sister, who is more pragmatic, or practical, refuses and begs Electra to be "wise." But Electra, who is dominated by her passion for revenge, is determined to do her duty to her father and exact justice. Learning that Orestes is actually alive fills her with joy, but she hides her happiness so that she and Orestes can fulfill their plot for revenge. She is pitiless toward her mother and stepfather as Orestes kills them, taking pleasure in their deaths.
Chrysothemis, although older than Orestes, was quite young when her father was killed. While she agrees with Electra that his murder was an evil deed, she feels powerless to do anything about it. She would rather forget the past and make the best of her lot, so she accepts the role of a dutiful daughter to her mother and stepfather. Chrysothemis is a bit of an optimist. She feels that accepting her mother and Aegisthus as Argos's rulers will preserve her freedom. Chrysothemis provides a counterpoint to Electra's thirst for revenge by counseling Electra to be wise—to let go of her anger and accept what she cannot change.
Clytemnestra may act as if she were justified in murdering Agamemnon, but the deed still torments her. Not only must she live in fear that her son, Orestes, may return any day to avenge his father's death, but she has had a dream about Agamemnon that seems to foretell her downfall. She hurries to send her obedient daughter, Chrysothemis, to decorate Agamemnon's tomb with gifts on her behalf, hoping to appease him. Clytemnestra is defensive and angry when confronted by her daughter Electra, who never lets her forget what she has done. She can finally relax when a messenger brings the news that Orestes has been killed in a chariot race. Maternal sadness takes second place to her relief, but it is short-lived. Orestes, still alive after all, comes to exact his revenge. She dies begging her son to show her the mercy she denied his father.
Orestes, although smuggled out of Mycenae as a small child, returns as an adult to exact vengeance. He has received instructions from Apollo's oracle and, in addition to seeking personal revenge, sees himself as an instrument of the god's justice. Having spent the majority of his life away and knowing his sister Electra only through their secret letters, Orestes dares not reveal his presence, even to her. When he realizes how deeply his fake "death" has wounded her, however, he relents and reveals his true identity. Still, like Electra, Orestes is content to wait for more than a fleeting reunion until their revenge is complete.