Now it was on this same night on which the cask was found that, as the storm still raged, a knock was heard at the cottage door. It startled all within, for who was there could have crossed the stream that now separated them from the mainland? It could surely be no mortal who stood without.
As the inhabitants of the little cottage sat silent, thinking these thoughts, the knock was heard again. It was followed by a low groan. Then the knight rose and took his sword from the wall where it had hung for many days. But the fisherman, watching him, shook his head as he muttered, 'A sword will be of but little use to-night.'
Undine meanwhile had gone toward the door. She did not open it, but she called out in a loud voice, 'Remember, whoever you be, spirit of earth or fire, that if harm befall us my uncle Kühleborn will punish you.'
These strange words made the knight marvel. But a voice answered the maiden, 'I am no wandering spirit, but an old frail man. For the love of God open your door and give me shelter from the storm.'
At these words Undine, holding a lamp high in one hand, flung the door wide open with the other. Before her stood an old priest, who looked upon her with surprise. How came so fair a maiden to be dwelling in so lonely a home? he wondered, and in his bewilderment he stood still outside the shelter and warmth which awaited him.
'Will you not enter, holy Father?' said Undine.
The priest roused himself to thank the beautiful maiden, and then entered the kitchen. Water flowed from his long robe and trickled from his long white beard and snowy locks.
'Come with me, Father,' said the fisherman, and he drew the priest into a little room and made him take off all his wet garments. Then, clad in a suit of dry clothes which belonged to his host, the priest returned to the kitchen.
The old woman pulled forward her own armchair and made the priest sit in it, while Undine brought a little stool and put it beneath the feet of the stranger.
Meanwhile food was placed before the priest. When he had eaten he was refreshed and able to tell his host how he had reached the island.
'It was but yesterday,' he said, 'that I was sailing across the lake, when a sudden storm arose. A wave dashed upon my boat, overturning it and throwing me on to the shore. I lay there stunned for some time. Then, as I slowly recovered my senses, I saw a footpath before me, and following it I reached the shelter of your cottage.'