One day , in a lake near his house , the Laird of Lorntie went to help a woman he thought drowning , and a servant of his pulled him back , warning that it was a mermaid , and the mermaid screamed after him that she would have killed him if it were not for his servant . One day , in a lake near his house , the Laird of Lorntie went to aid a woman he thought drowning ; a servant of his pulled him back , warning that it was a mermaid , and the mermaid screamed after that she would have killed him if it were not for his servant .