"Is Sally aboard?" she called to him.

"No, she went up the sh.o.r.e a ways--didn't say where," the captain replied, waving his hand upriver. "Ought to be back here any minute."

Sally, however, did not appear, and the _Queen_ pulled away without her.

Penny loitered on the dock for twenty minutes. The sun was hot and with nothing to do, time lay heavy upon her. It lacked a half hour before the _River Queen_ would return, and fully two hours before she was due to meet Jack. For lack of occupation, she walked upriver along the docks.

Buildings were few and far between. There were several fish houses, a boat rental place and the half-deserted amus.e.m.e.nt park. The beach beyond made easy walking, so Penny kept on. With quickening interest she saw that she was approaching a two-story building which appeared to stand on stilts over the water. Close by was a large, smoothly cemented area with overhead lights.

"That's the Harper place!" Penny recognized it. "With the dance area adjoining."

She moved on along the beach. Drawing closer to the building, she pa.s.sed a clump of bushes fringing the sand. The leaves stirred slightly though there was no breeze. Penny failed to notice the movement.

But as she pa.s.sed the bushes, a hand reached out and grasped her ankle.

Startled, Penny uttered a nervous cry.

"Be quiet, you goon!" a familiar voice bade.

It was Sally Barker crouched amid the foliage. Quickly she pulled Penny with her behind the bushes.

"Sally, what are you doing here?" Penny demanded.

"Watching that house. I saw you a long way down the beach."

"Anything doing?"

"A boat is coming in now. That's why I didn't want you to be seen."

A rowboat with an outboard, rapidly approached the Harper pier. Already it was making a wide sweep preparatory to a landing.

"Why, it's that fellow, Joe the Sweeper!" Penny exclaimed, peering out from the hiding place. "Who is steering the boat?"

"Claude Harper," Sally revealed. "Ma Harper's husband."

"Wonder what Joe would be doing here?"

"That's what I'd like to know myself," Sally returned grimly. "Joe isn't as stupid as he's given credit for being. He's crafty and mean, and being mixed up with the Harpers is no recommendation."

While the girls watched, the boat landed. The two men tied up the craft, and removing a burlap sack which apparently was filled with something heavy, carried it into the two-story house.

"I wish we knew what they brought here," Penny said. "Why not try to find out?"

"How?"

"Couldn't we sneak up to the house and peek in one of the windows?"

"We might be caught."

"True, but we'll learn nothing more here."

Debating a moment, the girls emerged from their hiding place. To reach the house they were compelled to cross an open stretch of beach. However, no one was to be seen outside the dwelling and their arrival appeared to attract no notice of anyone inside.

"How about that window at the east side?" Penny suggested.

The one she pointed out was half screened by bushes and at a level which would permit them to peer inside.

"Okay," agreed Sally, "but I'd hate to be caught at this business. The Harpers hate me and they would be mighty unpleasant if they came upon us snooping."

"What a harsh word!" chuckled Penny. "All this comes under the heading of investigation! The only difference is that Mr. Gandiss' detectives are paid and we aren't."

"If I could get the bra.s.s lantern back that would be pay enough for me,"

Sally returned.

Creeping to the window, the girls cautiously peeped into the house. The panes were so dirty it was hard to see inside. But they were able to distinguish three persons sitting at a living room table. Papers were spread out before them, and they were adding figures. There was no sign of the sack which had been carried into the house.

"Who are they?" Penny asked her companion.

"Joe the Sweeper, Ma Harper and her husband. Another woman is coming into the room now. But she's only a stupid houseworker Ma hires by the week."

Sally moved backwards, intending to give Penny her place at the window.

Inadvertently, she stepped on a stick which broke in two with a snap.

Though the sound was not loud, it apparently was heard by those inside the house.

For immediately Claude Harper shoved back his chair and started toward the window.

"What was that?" the girls heard him mutter. "I thought I heard someone outside."

"Quick! Crouch down or he'll see us!" Penny warned, pulling Sally to the ground.

Claude Harper, a sallow-faced man in dirty leather jacket, appeared at the window. To the alarm of the girls, he thrust up the sash. In plain view, should he peer down over the ledge, they held their breath.

The man, however, gazed toward the boat docks. "I don't see anyone," he reported to his companions. "I was sure I heard something--" he broke off, ending sharply: "And I did too!"

"What is it, Claude?" his wife called.

"Anyone been here this afternoon?" he demanded.

"Nary a soul until you came."

"Take a look at those shoetracks in the sand!"

Hearing the words, Penny and Sally gazed behind them. From the bush on the beach to the wall where they crouched, led a telltale trail.

"I'll go outside and look around!" Harper said to his wife. He slammed down the window.

"We're sunk!" Sally moaned. "We can't run across the beach without being seen, and we're certain to be caught here."

Keeping close to the wall, treading in firm earth which left no visible shoemarks, the girls crept around the building corner. The slamming of a door warned them that Claude Harper already was on their trail.