Lake of Darkness — Frances Cowen

A beautiful old castle inhabited by an evil, twisted man; acres and acres of magnificent gardens marred by the bottomless lake of darkness that had claimed the lives of two students . . . and was reputedly responsible for the recent disappearance of a third.

Agnes Macintosh entered this strange setting in a dangerous attempt to reconstruct the life she had buried twenty-five years ago. For she had reason to believe that the young man who had disappeared was her grandson! And then lovely Sally Hagen turned up, so desperate to learn the whereabouts of her brother that she became price of a deadly silence . . . .

Two women tried to make the lake give up its secret - and played into the hands of a madman.