As the Argives pass through Nemea on their way to Thebes, they are spotted by the god Bacchus who harbours sympathies for the Thebans. To prevent the army's arrival, he withdraws all water from the area. The Argives are struck by a parching thirst but they are saved by a young woman named Hypsipyle who shows them the way to a nearby stream. After they drink from the muddy river, Hypsipyle reveals that she is the daughter of Thoas, the former king of the island of Lemnos.