This play takes place about seven years after the events in Agamemnon. The scene is in front of the tomb of Agamemnon. Orestes and Pylades enter. They are both dressed as travelers. Orestes places two locks of his hair on Agamemnon's tomb — one in honor of the river god Inachus, who watched over him in boyhood, and the other dedicated to his father, as compensation for not having been present to mourn at his funeral. Looking up, Orestes sees Electra and a group of women dressed in black approaching the tomb. Orestes utters a brief prayer to Zeus for help in avenging Agamemnon's murder; then the two young men hide in order to observe the women and learn why they have come to the tomb.
This scene is unusually short because the first part of the prologue is missing in ancient manuscripts of the play. In the lost portion, Orestes probably told about Apollo's command to avenge Agamemnon since from the outset of the play Orestes seems to regard the murder of Clytaemestra as his unquestioned duty. He has come to Agamemnon's tomb to ask the dead man's spirit to assist in this undertaking and does not immediately identify himself to Electra and the women because of a prudent sense of caution.