Egeon, a merchant from Syracusae, is arrested for having illegally entered Ephesus. He tells the story of how he lost his wife and an infant son; the remaining identical-twin son grew up and set out to find his lost brother; Egeon in turn journeyed in search of the son he had raised. His journey has brought him to Ephesus. Now Egeon is given until the end of the day to raise ransom money. If he fails, he will be executed.