In a cottage by a lake a farmer, hard-working and honest, lives alone (but for his dog) and longs for a companion and helpmate. One day, when he is out at work, a large shell emerges from the lake and from it steps a nymph eager to help him: while he is out she cooks him a meal. The farmer is surprised and delighted, and spies next day on his secret visitor. He asks her to share her life with him, and the nymph eventually agrees. They rejoice in their mutual happiness. In the second part, after a period of twenty years during which the nymph has borne the farmer a son and a daughter, she realises that her allotted period amongst humans has come to an end, and departs sadly back to her watery domain. Her descendants, however, live on in the country, becoming prosperous farming folk in their turn.