Nephele of Athamas was born from the sky above Boeotia, a nymph of the mist and the clouds who drifted down to earth at the command of Zeus, the king of the gods. The Greeks called her a cloud-nymph, one of the minor deities who governed the vapours and the fogs, and they said that she was as beautiful as a morning rainbow and as insubstantial as the dew. Zeus gave her to Athamas, the king of Orchomenus in Boeotia, as a divine bride, a gift that signified the god's favour upon the king and his kingdom. Athamas received her with gratitude and married her with proper ceremony, and she bore him two children: a son named Phrixus and a daughter named Helle. The children were beautiful and healthy, and for a time the family was happy. The people of Orchomenus honoured Nephele as their queen, and the harvests were good, and the cattle fat, for a cloud-nymph brings moisture and fertility to the land she loves.

But Nephele was a creature of mist and air, and Athamas was a man of flesh and blood. He grew restless in his marriage to a being who could not share the warmth of a mortal hearth, who drifted through the palace like a cool breeze and who vanished into the sky whenever she wished. He desired a mortal wife, someone solid and warm who would not dissolve into fog when he held her too tightly. He cast Nephele aside and married Ino, the daughter of Cadmus, the founder of Thebes, and Harmonia, the daughter of Ares and Aphrodite. Ino was mortal, beautiful, and ambitious, and she bore Athamas two sons of his own: Learchus and Melicertes. Nephele, abandoned, returned to her place in the sky, but she did not forget her children. She watched them from above, and she saw the danger that approached them in the shape of their new stepmother.

Ino's ambition turned to malice when she saw that Athamas still loved his first children, and that the people of Orchomenus still honoured Phrixus as the heir to the throne. She devised a plot to destroy them. She persuaded the women of Orchomenus to roast the seed corn before it was planted, so that when the sowing season came, nothing sprouted from the earth. The crops failed, the cattle sickened, and famine spread across Boeotia. Athamas sent messengers to Delphi, the oracle of Apollo, to ask what sin had brought this disaster upon his kingdom. Ino bribed the messengers to return with a false prophecy: the famine would not end until Phrixus and Helle were sacrificed to Zeus on the altar of Mount Laphystius.

Athamas, desperate to save his people, agreed to the sacrifice. He led his children to the mountain, and the priests prepared the altar and the knife. But Nephele, watching from her place in the sky, saw what was happening. She had never abandoned her children, though she had been abandoned by their father, and she would not let them die. She sent a golden ram, a creature with a fleece of pure gold and the power of flight, down from the heavens. The ram appeared beside the altar, and Phrixus and Helle, understanding that their mother had sent it, climbed upon its back. The ram leaped into the air and carried them across the sky, its golden fleece blazing in the sunlight like a second sun.

The flight was miraculous and terrible. The ram soared over mountains and seas, its hooves barely touching the clouds, and the children clung to its golden fleece with desperate hands. But Helle, the younger and more frightened of the two, grew dizzy with the height and the speed. She loosened her grip, she slipped, and she fell. She tumbled through the air and struck the water below, the narrow strait that separates Europe from Asia, and she drowned before her brother's eyes. The sea closed over her, and from that day forward the strait was called the Hellespont, the sea of Helle, and every sailor who passed through it remembered the girl who fell from a golden ram. Phrixus, weeping, clung on, and the ram carried him to the far shore of the Black Sea, to the land of Colchis, where King Aeetes, the son of Helios, the sun-god, received him as a guest and gave him his daughter Chalciope in marriage. Phrixus sacrificed the golden ram to Zeus and gave its fleece to Aeetes, who hung it upon an oak tree in a sacred grove and set a dragon to guard it, and there it remained until Jason and the Argonauts came to claim it a generation later.

Nephele's story does not end with the rescue. She remained in the sky, a cloud among clouds, and the Greeks sometimes saw her in the mists that gathered around mountain peaks or in the fogs that rolled across the Boeotian plain. She was worshipped in some places as a goddess of rain and moisture, a minor deity who brought the spring showers that made the crops grow. But her true legacy was the Golden Fleece, the treasure that hung in Colchis and drew Jason and his crew on the most famous voyage in Greek mythology, and the Hellespont, the waterway that every Greek sailor knew by the name of the daughter she could not save.