Below the present surface of this lake was once a level plain, over one part of which towered a castle, or dun at least. A cavern under this castle led to some unexplored region, and a beautiful spring-well lay not far from its mouth. The lord of the dun was informed that three beautiful women were seen at times to come forth from the cavern's mouth, on calm moonlight nights, and bathe in the well; and the tale was not told to inattentive ears. He concealed himself just within the entrance of the passage, and saw the three beauties pass forth into the moonlight. He waited impatiently till they were returning, and he allowed two of them to glide by his hiding-place. As the third, who was the youngest and most beautiful, went by, he grasped her, and bore her into the open air. The others fled into the cavern, and the imprisoned nymph pleaded hard for her liberty. But he was handsome and gentle, and resolute at the same time, and at last she agreed to reign as mistress of his heart and his domains. They lived in happiness for many years, and two children were born to them. She had made it a condition that he should never invite company to the castle, and for many years he felt no desire to break his engagement.

Having in his stables a fine race-horse, a desire of going to the races of Kood at length seized on him, and he asked permission to attend that assembly. She gave consent, but warned him against bringing home any friends or acquaintance he might meet there. He returned home alone in the evening, rejoicing in a prize won by his steed, and induced his Sighe lady to agree to his repeating the excursion next day. Her consent was granted, accompanied with a solemn caution. The second evening also he kept to his word. But woe the while! on the third day some thoughtless and other envious acquaintances beset him, intoxicated him, learned his secret, and were invited to accompany him to his castle, and be introduced to his lady that evening. The beautiful Sighe had been watching for his return, and when she saw him cross the plain, surrounded by a disorderly crowd, he and they indulging in boisterous mirth, her love and esteem for him melted into thin air. The noise of the unthinking group ceased as they beheld a woman of superhuman beauty advancing towards them from the castle door, leading a child by each hand. The chief s heart began to throb wildly, and immediately after he uttered a wild cry of anguish, and rushed on as he saw her and his children disappear in the enchanted spring. The wonder and surprise of his companions were soon changed into personal fears, for water began to burst forth in a large body from the well and fill the plain. Out it kept rushing till it acquired the level it occupies at this day-a signal warning against all unsuitable associates, and breaches of solemn engagements.