It's the story of a woman who was a priestess of Poseidon. A woman who bore the children of the god she served - or perhaps only of his rival. For Neptune disguised himself as Poseidon and deceived her, coveting as he did all that Poseidon had and was. Until one day, Poseidon discovered them together. In his wrath, he cursed the woman such that she became a monstrous gorgon, and her gaze caught Neptune and petrified him. Then Poseidon declared that such would be the fate of any upon whom she set eyes that did not truly bear his blood, and he withdrew his river from the temple and he left her.
One of the woman's children heard their mother's crying, and came to her and was struck stone. Then those of her children that remained were much afraid, and they barred the temple door upon her and the other priestesses. The woman fled into the deepest passages of the temple, whilst the handmaidens of the temple turned upon each other with recriminations as they succumbed to their hunger.
Left without their mother, the children grew wild and uneducated, becoming little more than barbarians. Fearing their mother, but ashamed of their treatment of her, they told of her affliction, but not that Neptune had deceived her. And so every now and again a man would take up his sword and go into the temple to slay the dreadful monster that laired there. And so the statues in the temple grew in number, one by one.
Then one day, a woman arrived, and heard the story. But she searched deeper than the tale of the monster, and was moved to pity, for she had a son herself, and understood the bond that lay between mother and child. And understanding that bond, she said "these children may be of one father or the other, yet all are of the same mother, that which should be the closest bond of all. But these children have turned from their mother, and so the bond is weakened and cannot overcome the curse." Then she sat and thought upon how the children might be reconciled with their mother.
She knew that the mother's love for her children was great, as was the children's for their mother. But a mortal, no matter how strong, cannot defy a god without the assistance of another god. Therefore, she began by journeying to Eleusis to ask for the favor of Demeter. Speaking as a mother, she beseached Demeter to recall a mother's pain at being separated from her beloved child--as Demeter was from Persephone--and asked her to provide the divine assistance necessary to overthrow the curse. Like Athena before her, Demeter would help a mortal to thwart Poseidon.
Then the woman went down to the children, and spoke to them, saying "grievously have you wronged your mother, that you would let it be thought that she would willingly be unfaithful. It is not her infidelity that lies between you, but your own. And she went to the mother, and said "you have been thrice wronged, lady; by Neptune and by Poseidon and by your own children. But your children in their humility have recognised their fault, and crave your forgiveness". Then she brought the children before her--and it then that Poseidon intervened. He brought down a terrible storm, seeking to drive the children to shelter and way from their mother. And here, too, did Demeter intervene: as the goddess of the harvest, she transformed the storm into a nourishing rain; at the same time, she tricked Poseidon into redoubling his efforts, so that he darkened the sky with the rain clouds, blotting out all light...and making it possible for the woman to bring the children to their mother free from fear of meeting her gaze. As each spoke their shame one of the serpents upon her head withered and died, until at last only one remained.
Then the children were dismayed, but the wise woman knew that one of the offspring yet remained unreconciled, so she brought the statue before its mother. The mother wept bitter tears, and said "grievously have I wronged you, my son, who alone of all of my children came to my aid", and her tears ran out of the temple so that water flowed from it once more - and it flows still. Then she took the snake, and crushed its head against the statue, and where its blood ran, flesh appeared. The mother and her children embraced, and ever afterwards became the closest of families. Every year they celebrate their reunion, and it is said that on that day, if a mother forgives a child of the wrong they have done them, or a child their mother, their tears can wash away the obstacles that stand between them.