The inner court of the palace at Mycenae.
Evening. Maidservants deplore the demented conduct of Elektra, daughter of queen Clytemnestra. Consumed with hate, she is in the habit of prowling about the courtyard, and howling like the dogs with which her mother and her mother’s lover Aegisthus have condemned her to live, after murdering her father Agamemnon. Only one very young maidservant feels pity for Elektra’s wretched fate. Elektra now appears. Obsessed by memories of her father’s death, she has long been waiting for the return of her brother Orestes to avenge the murder of Agamemnon by killing Clytemnestra and Aegisthus. Her younger sister, Chrysothemis, is certain, however, that Orestes will never come back to Mycenae, and exhorts Elektra to escape, because, she has heard that Clytemnestra and Aegisthus, who fear Elektra’s craving for revenge against them, have decided to imprison her sister in a dark tower. But Elektra violently rejects the advice of Chrysothemis. After chasing her off, she prepares to meet her mother. Clytemnestra is plagued by nightmares, in which her son Orestes attempts to kill her. Terrified by this vision, the queen orders constant sacrifices and wanders distraught through the palace, laden with amulets. She even has no hesitation in asking her daughter for a remedy against the horror that haunts her nights. Elektra replies mysteriously that her peace of mind will be restored when a woman has been struck to death by a man. Whereupon she reveals to her mother the grim mystery: it is she herself who shall fall beneath the mortal blows of her own son. Their dialogue is interrupted by a maidservant who announces to Clytemnestra the death of Orestes: two messengers are on their way to the palace with proof of his death. A servant is dispatched to warn Aegisthus. In vain Elektra begs her sister for help, promising in exchange to be her faithful companion. Eventually she resolves to act alone, but the first messenger interrupts her preparations for revenge. The stranger is in reality Orestes, who has come to Mycenae in disguise to avenge his father’s death. After some hesitation, Elektra and her brother recognize each other. The arrival of the second messenger, who is actually Orestes’s tutor, reminds them both, however, that the moment of vengeance is imminent. Orestes goes into the palace and slays his mother. The maids rush to her aid but recoil in fear upon seeing Aegisthus, who is welcomed by Elektra. Slyly she declares obedience to him and lures him into the palace.With no means of escape, he too is killed by Orestes. The people joyfully acclaim their liberator. Elektra dances a few frenzied steps, then swoons and collapses on the floor. Chrysothemis invokes her brother’s name.