The first play of the Oresteia trilogy, Agamemnon tells the story of Argos's king, home victoriously after the Trojan War. Clytaemnestra, nursing a grudge because Agamemnon killed their daughter Iphigenia, has taken a lover—Aegisthus. Soon after Agamemnon's return, Clytaemnestra kills him and with Aegisthus becomes ruler of Argos.