This is a short and humorous story about a couple who had a frog for a  son and how he later went on to become a prince. Once there was a king's attendant and his wife who did not have any children of their own. The wife's knee always hurt and one night while sitting by the fire a frog came out of it. Not could only could the frog talk, it was also able to do housework. It was so special, in fact, that it married the king's daughter. In actuality, the frog was the son of the serpent-spirit king. Once, when he shed his frog skin to go and participate in a horse race, the princess learned of this and burnt the frog skin in a fire. After the frog skin was burnt, the serpent-spirit prince and the princess lived together happily.