Iolaus, Heracles' nephew and his companion during his Twelve Labours but now an old man, is in hiding with Heracles' fatherless children at the altar of the temple of Zeus at Marathon, near Athens. They have been moving from city to city, as Iolaus tries to protect them from the vengeful King Eurystheus of Argos, who has vowed to kill them. A herald from Eurystheus appears calling on them once more to return to Argos to face the consequences, and Iolaus begs the Chorus of aged Athenians to take pity and help them.