Walk Softly, Doctor

"Dr. Lynne Vicars felt the tears come to her eyes as she bent over the form of her dying father. His voice was weak. "There is a man,' he gasped. 'A man I should have warned you about many years ago.' Then his voice was still as death overtook him.
Puzzled, Lynne returned to her hospital post and to the two men in her life--only to be plunged into a situation of mounting terror as someone--someone unseen--closed in on her. Could it have been one of the two who claimed to love her? Or could it have been an unseen third?"