The other two detectives disappeared into the darkness. Twenty minutes later they returned to report that they had found no one at the old house, although there was evidence of a hurried departure. The shots previously fired by the detectives had served as a warning.
Riding back to the city with the handcuffed prisoner, Penny wondered how faithfully her father's investigators had followed her movements of the evening. Had they noted her call at the Davis home or the visit she and Susan had paid to the Hamilton building?
"I suppose I've been trailed everywhere to-night," she ventured conversationally.
"You almost gave us the slip," one of the detectives told her with a smile. "In fact, you did for awhile."
"You turned off somewhere and we lost you for a time. Didn't locate you again until you turned up at your own home."
Penny was relieved. The detectives could not possibly be aware of the secret entrance into the Hamilton Plant. She would still be the first to report the discovery to her father.
The detectives dropped Penny at her own home after explaining that it might be necessary for her to appear in court later on to identify the prisoner.
"I'll be very glad to do it," Penny promised.
As she ran up the front steps the door was flung open and Mrs. Gallup rushed out to meet her. She flung her arms about the girl.
"Penny!" she cried tremulously. "How thankful I am that you are safe! Your father came home fifteen minutes ago. Then we knew that the telephone call was a fake."
"Then I guess he'll learn the truth in a few minutes if he's still there."
In the midst of the tale, a car was heard on the driveway, and a minute later Mr. Nichols entered the house. Although he was never inclined to be demonstrative, the detective clasped his daughter in his arms and Penny noticed that his hands trembled slightly.
"I've just heard the entire story at the police station," he told her. "You gave me a terrific scare, Penny."
"I gave myself one, too. If it hadn't been for your men who shadowed me, I'm afraid I'd never have returned to tell the tale."
"I doubt that the gangsters would have actually harmed you, but they would have used you as a weapon to strike back at me. I am sorry about having you trailed, Penny, but you understand my position. I was afraid of this very thing."