The Nurse and the Spying Stranger — Diane Frazer

Beginning of peril...

It all started when private-duty nurse Phyllis MacKenzie answered the phone.
"Hello, hello," Phyllis said.
"Who is this? Hello-"
She could hear someone breathing at the other end. Breathing, that was all.
She hung up.
"Who was that?" asked Mrs. Choate, her invalid patient.
"Wrong number, I guess," said Phyllis. "No one said anything."
But a chill presentiment swept over her....

That was how it started, but before it ended Mrs. Choate's lovely eight-year-old granddaughter, Gretchen, was in peril of her life.