A man has come out of the sea -- brain damaged in a fight with a terrible giant -- remembering very little about himself. He knows his name is Proteus, and that he was sent to join Jason and the Argonauts as they embarked on the greatest journey the world has ever known.

When Princess Medea, who also has an interest in Jason's journey, is struck by Cupid's arrow, she falls so desperately in love with Jason that she is ready to betray her father and to lure her own brother to his death, so that Jason may win the Golden Fleece.

Neither Medea nor Jason, knows that there is a god amongst the crew. This is one more item that Proteus has forgotten.