Eteocles prepares to defend the city of Thebes against his brother Polynices and the invading Argive army. As the king of Thebes, Eteocles must organize the city's defense while grappling with the curse placed upon his house by his father, Oedipus. He assigns commanders to each of the seven gates, ultimately choosing to face his brother in single combat at the seventh gate. The narrative unfolds through formal dialogue and choral odes, adhering to the rigid structure of ancient Greek tragedy. The conflict pits the necessity of civic duty against the inevitability of ancestral fate.

Readers and scholars frequently highlight the play's intense focus on the psychological burden of leadership during wartime. Discussion often centers on the stark contrast between the choral laments and the rigid, militaristic resolve of Eteocles. Critics emphasize the effectiveness of the play's atmosphere in conveying the claustrophobia of a besieged city. The work is widely studied for its structural precision and its role in the broader Theban cycle of Greek mythology. Readers often note that the play serves as a foundational example of how ancient dramatists utilized ritual to explore complex moral dilemmas.