Seven Against Thebes is part of the Oedipus myth; it would fit between Sophocles’ Oedipus at Colonus and Antigone. However, this Aeschylus play actually features Eteocles, who doesn’t show up in any of the Sophocles plays.
Eteocles and his brother Polyneices are the sons of Oedipus and they’ve inherited the throne, which they decided to share on a rotating annual basis. However, this plan has predictably poor results when Eteocles decides he doesn’t want to give up the throne (shock of all shocks). To try and enforce their agreement, Polyneices has raised an army and besieged Thebes, sending seven champions to the seven gates of the city. Seven Against Thebes begins at this moment of crisis—an army stands at the city’s walls and Eteocles must choose seven champions to face the invaders’ warriors. When he learns that Polyneices will be personally attacking the seventh gate, Eteocles chooses to face his brother himself despite the protests of everyone around him. Both men—Eteocles and Polyneices—are killed in the combat.
The brothers’ mutual destruction fulfills the curse on the house of Laius, placed on their grandfather. Laius was told by the Oracle never to have children, but while drunk Laius impregnated his wife Jokasta. For this the gods cursed the house of Laius, dooming them to destruction, a doom carried out in Seven Against Thebes. Eteocles and Polyneices are the sons of Oedipus, grandsons of Lauis, and their fate is to destroy one another in battle and therefore end the line of male descent from Laius.
Aeschylus’ play opens with Eteocles discussing the military situation and making an inspirational speech to the people of Thebes. Despite Eteocles’ speech, the Chorus of Theban Women begin to panic and beg the gods for protection. Eteocles chastises the Chorus for speaking of defeat at a time of war, and then debate whether or not offering prayers for deliverance is beneficial or invites defeat by entertaining the notion of defeat. Following this debate there is a long and beautifully moving passage about the brutal effects of war on captured cities. After this passage, a soldier comes in to report to Eteocles about the seven champions stationed at the various gates. This dialogic section goes back and forth in a very traditional formula for ancient literature: the soldier describes an enemy champion with his arms, armor, equipment, and behavior; Eteocles assigns a champion of his own, whose characteristics mirror/foil the characteristics of the enemy champion; and the Chorus prays/laments for the success of their champion against the enemy. When the final champion is named as Polyneices, Eteocles calls for his armor to go and fight his brother personally. The Chorus and soldiers protest, begging Eteocles not to fight his brother for fear of fulfilling the curse. Eteocles ignores these supplications and goes to the battle. Soon a soldier returns and informs the Chorus that the city is saved but that the sons of Oedipus killed one another. The Chorus laments the inevitability of fate when a curse has been proclaimed and will be enforced by the Furies. Ismene and Antigone—Oedipus’ daughters/sisters, and Eteocles’ and Polyneices’ sisters—enter to lament their fate and the fate of their brothers, then a Herald enters to announce that the state’s regents have declared that Eteocles should be honorably buried but Polyneices should be left dishonorably unburied because he made war against his home city. Antigone refuses to assent to this, saying that even if the state declares that he should not be buried, she will bury Polyneices himself (which leads into the events of Sophocles’ Antigone).