In the waters that surround Knockdolian Castle in Strathclyde, Scotland, there used to come a mermaid after the sun sunk below the sea and the air was filled with darkness. The mermaid loved to climb upon a rock near the shore and fill the starlit night with song.

The Lady of Knockdolian had a wee bairn (infant). The mermaid's singing wakened the bairn, and preferring her baby to sleep soundly through the night, the Lady attempted to put an end to the mermaid's visits to the waters along the shore.

Night after night the Lady called out to the mermaid to cease her noise to no avail. The mermaid sang on all the while the tide lay low, gracefully seated upon her rocky pedestal. Tired and irritable from many a sleepless night the Lady of Knockdolian finally had an idea she was sure would work. She called upon her groom and bade him to wade out into the sea and strike the stone to bits.

That night the mermaid swam in from the sea to find her favorite perch gone. She grew very distraught and thrashed about angrily in the sea. Then suddenly she drew well up out of the waves and sang out in the direction of the castle:

The Lady of Knockdolian and her bairn slept well that night. But a few nights later the Lady entered the nursery to find the cradle overturned and the babe dead beneath it. Never again did the Lady's womb quicken and the family died out. It seems the mermaid's last song for the Lady of Knockdolian was a curse well seeded.