[6] The themes in Children of Heracles focus on the bravery of women, revenge, and the hardships and consequences of war.

Other characters include Hyllus, Heracles's eldest son and the herald Copreus.

The play begins at the altar of Zeus at Marathon where Heracles's children, Iolaus and Alcmene take shelter.

King Eurystheus is determined to kill the children, wary that they will want to avenge their father.

Demophon is prepared to protect the children even at the cost of fighting a war against Eurystheus, but after consulting with the oracles, he learns that the Athenians will be victorious only if they sacrifice a maiden of noble birth to the goddess Persephone, "They bid me to sacrifice a maiden to the daughter of Demeter, a maiden daughter of a noble father, to rout the enemy and save the city.

"[9] Reluctant, Demophon tells Iolaus that as much as he would like to help, he will not sacrifice his own daughter or compel any of the Athenians to do so.

Iolaus, realizing that he and the children will have to leave Athens and seek refuge elsewhere, despairs.

Realizing her family's predicament, she courageously offers herself as the sacrificial victim, refusing a lottery among other girls.

Eurystheus accepts his fate and tells them a prophecy of how his spirit will protect the city from the descendants of Heracles's children if they slay and bury him, "And you shall have a double profit from me: by dying I shall bring benefit to you and harm to the Heraclids.

The play was not popular, and had been deemed by Ulrich von Wilamowitz-Moellendorff, an expert on ancient Greek literature, to be irrelevant.