n't get along without
you."

Mrs. Gallup sniffed.

"I do the best I can. The coffee does taste all right, doesn't it?"

"It's perfect."

"When your father's working on a hard case he always likes it strong as
lye," the housekeeper complained. "But I know he was worried about
something this morning."

"What makes you think so?"

"I heard him muttering to himself. Something about the stupidity of
the police. It seems they let some crook get away last night after
your father had laid careful plans to catch him."

"Not Rap Molberg?"

"I think that was the name. Mr. Nichols didn't tell me anything, I
just heard him talking it over with himself."

"It's the only person he will discuss his business with," Penny
chuckled.

After Mrs. Gallup had gone back into the kitchen she mulled over the
information which the housekeeper had given her. It struck her as
probable that the car which she had seen vanish down the dead-end
street had been driven by Rap Molberg or one of his confederates.

"I wish I could have talked with Dad about it before he left the
house," she thought.

Penny had not forgotten her resolution to visit the Hamilton Plant by
daylight. As soon as she had helped Mrs. Gallup with the dishes, she
left the house, walking directly to the scene of the previous evening's
adventure.

The street was deserted. No one questioned her actions as she made a
careful inspection of the old building which had housed the Hamilton
Manufacturing Company until its failure. She examined the walls inch
by inch, but although she was convinced it was there, she could find no
hidden entrance.

Regardless of her failure to find evidence, Penny was unwilling to give
up her original theory. She remained unshaken in her belief that the
mysterious automobile had disappeared into the Hamilton building.

"There's no other place it could have gone," she reasoned. "I'll talk
it over with Dad and see what he thinks."

When she stopped at his office, Mr. Nichols was not there nor could
Miss Arrow tell her when he might return.

The detective did not come home for luncheon and late in the afternoon
telephoned to say that he would take dinner downtown. Rather than
spend an evening alone Penny called Susan, arranging that they should
go to the library together.

The girls spent an hour in the reading room, but for some reason Penny
could not interest herself in the magazines. She kept turning through
them and laying