Penny struggled to free herself but could not. The man's grip was like steel.

"So you were spying!" he exclaimed harshly.

"I--I was just watching," Penny stammered. "Don't you remember me? I am the girl who pulled you out of the river when your car went over the drawbridge."

The man looked closely at her, and for an instant she dared hope that he would recall her with grat.i.tude. But his face hardened again and he said unfeelingly:

"You know entirely too much, my little girl. This is one story you will never write for your father's paper. Your curiosity has proven your undoing. You share the fate of your very good friend."

With a sinking heart Penny realized by the man's words that he knew her to be the daughter of a newspaper publisher, and that he had guessed her part in the trick played upon him.

"Down you go!" Dietz said harshly.

As he dragged her toward the pool, Penny screamed at the top of her lungs. A hand was clapped over her mouth. She bit it savagely, but her efforts to free herself were of no avail.

The men shoved her headlong down the stone stairway into the pit.

"Now scream as much as you like," Aaron Dietz hurled after her. "No one will hear you."

The heavy stone slab dropped into place.

Penny picked herself up from the steps. Terror gripped her, and with a sob she called frantically:

"Mr. Atherwald! Mr. Atherwald!"

"Here at the bottom of the steps," he answered with a groan.

"Are you hurt?"

"Only bruised. But my hands are still in cuffs."

Penny limped down the stairway and helped the man to his feet.

"We're done for now," he said. "No one will ever look for us down in this vault. And our cries will never be heard."

"Don't give up," Penny murmured encouragingly. "We may be able to lift the stone. Come let's try."

Mounting the stairs, they applied their shoulders to the ma.s.sive door, but their best efforts did not raise it an inch.

"Listen!" cried Atherwald suddenly.

They both could hear the sound of water running into the empty pool.

"In an hour's time no one will ever guess that a hidden vault lies beneath the tank!" Atherwald groaned. "We're doomed!"

"If we can hear the water splashing above us, our voices might carry!"

Penny reasoned. "Let's cry out for help. Now, together!"

They shouted over and over until their voices failed them. Then, completely discouraged, they sagged down on the stairway to rest.

"Nothing went as I planned," Penny said dismally. "I really thought the gold was hidden in this vault. If the men had found it, they would have spent hours removing the loot to their boat. Jerry would have come with the police and everything would have been all right."

Grant Atherwald was not listening to the girl's words. He struggled to his feet, pressing his ear against the trapdoor.

"The water has stopped running!"

"Are you sure?" Penny sprang up and stood beside him, listening.

"Yes, and I hear voices!"

With one accord, they shouted for help. Could it be imagination or did they hear an answering cry? As they repeated their frantic call, there was a sc.r.a.ping on the stone above their heads.

"Stand away," ordered a m.u.f.fled voice.

Before Penny and the bridegroom could obey, the great door lifted. A deluge of water poured in, its force nearly washing them from the steps.

But in another moment the pa.s.sage was clear and they stumbled up through the rectangular opening.

Jerry grasped Penny's hand, helping her out of the vault. One of the blue-coated policemen aided Atherwald, unfastening the handcuffs which held him a prisoner.

"You're all right, Penny?" the reporter asked anxiously.

"I--I feel like a drowned rat," she laughed, shaking water out of her hair. Then, with a quick change of mood she asked: "Did you get Aaron Dietz and his men?"

"No," Jerry answered in disgust. "When we crossed the river five minutes ago, the cruiser was still there. No sign of anyone around. I brought the police here, and now I suppose they've made their get-away."

"Oh, Jerry, we can't let them escape! Send the police--"

"Now don't get worked up," the reporter soothed. "A squad started back just as soon as we found out what had happened here."

"Dietz and his men must have seen the police crossing the river,"

speculated Penny. "They may have hidden in the bushes, biding their time.

By now they've slipped away in their boat."

"I'm afraid of it," Jerry admitted. "I traveled as fast as I could."

As one of the policemen lifted Penny out of the pool, a noise which sounded like the back-firing of an automobile, broke the stillness of the night. It was followed by a volley of similar sounds.

"Gunfire!" exclaimed Penny.

The policemen started at a run through the woods toward the place where the white cruiser had last been seen. Penny hesitated, and then took the opposite direction, coming out of the woods at a point directly opposite the drawbridge.

Gazing far up the river she could see the white cruiser, flashes of fire coming from the cabin window as the desperadoes exchanged shots with the police, who were concealed in the woods.

"That boat will try to run for it in another minute," Penny thought. "If only the drawbridge were down!"

Kicking off her shoes, she dived into the water, swimming diagonally across the river to take advantage of the swift current. Her powerful strokes brought her to shallow water and she waded ash.o.r.e through ankle-deep mud. As she scrambled up the slippery bank, her wet clothing plastered to her body, she heard the roar of the cruiser's motor.

"They've started the engine!" she thought. "In another minute the boat will be at the bridge. Hurry! Hurry!"