Dorothy’s vigorous motion forced her assailant to relax his grip upon her throat, and as she felt his weight upon her shoulders, she lunged down and backward. There was a dull, cracking thud, and the sound of a body falling. The back of her head struck one of the timbers that supported the ceiling of the tunnel. The place seemed to whirl round and round and glittering sparks danced before her eyes. When this sensation ceased, Dorothy leaned back against the post into which she had flung herself in her apparently successful effort to shake off her opponent.

With the realization that the attack had halted and that her assailant had either made his escape or was incapacitated, she fumbled in her pocket for a match.

“Where are you, Dorothy?” Bill’s voice called from the dark void.

“Right here, old thing—by the wall.”

She struck a light.

“All right?”

He looked pale and shaken in the flicker of the tiny flame. She saw that he grasped the crowbar.

“A bit woozy,” she replied, and lit the candle on the table. “Cracked my head on a beam or something.”

“That bearded guy didn’t hurt you?”

“He didn’t get a chance. Which way do you think he went?”

Bill laughed softly. “You put him out of business. Look!”

He pointed toward an upright and Dorothy saw a crumpled figure lying huddled at the base of the post.

“Goodness! You don’t think I’ve finished him?” she breathed in horrified alarm.

“No such luck,” he affirmed callously and bent over the man’s body. “Sit down until you feel better. This chap is only stunned. I’ll take care of him.”

Dorothy stumbled over to the table. Near-by was a chair. She dropped into it.

“He bumped his skull on this post,” Bill went on. “No great damage, I guess. Funny—whenever there’s a rough-house in the dark, somebody invariably gets a broken head. The three of us are even now.”

“What are you going to do with him?” Her dizziness was passing.

“Oh, I’ll give him as good as he gave me, and lash him to this upright.”

He busied himself tying up the unconscious smuggler. When he had finished, he looked up and beckoned to Dorothy.

“Come over here. He’s plenty secure now. This rope held me, I guess it’ll hold him.”

“What are you going to do now?”

“Find out who this chap really is.”

His fingers peeled off the false beard and Dorothy cried out in astonishment.

“Mr. Tracey!” she gasped.

“It’s Tracey, all right!”

“But who’d have thought that sleek pussy cat was mixed up in this? Aren’t you surprised, Bill?”

“Not very. When his car had the breakdown this morning I began to suspect. The whole thing was too darn opportune. He was part of their system of watchers, of course. Probably wanted to find out how we’d taken their warning.”

“But surely Mr. Holloway can have nothing to do with it! He’s such a sweet old man.”

Billy transferred two revolvers from Tracey’s belt to his own.

“If you want my candid opinion,” he said, “Old Holloway is the leader and brains of the gang. Only it’s going to be the dickens and all to prove it in a court of law.”

Dorothy stared at him incredulously. “Why, Bill—are you sure?”

“Why not? He’s just a double-dealer, that’s all. That wise old bird is certain to have a flock of cast iron alibis up his sleeve. He must have made more than enough money out of this diamond smuggling to keep Tracey’s mouth shut—and the mouths of any others who may be corralled.”

“I’ve got a hunch,” said Dorothy.

“Let’s have it.”

“Not yet. I want to chew it over a bit. Let’s go back now and get help.”

“That’s for you to do. I’m going on to the Castle and surprise whoever’s there. I don’t think they have a suspicion of what has happened down here. Tracey never got that far, I’m sure of it.”

“Well, you can take it from me that you’re not going alone. I’m coming with you.”

Bill hesitated.

“Well, perhaps that’s the best way, after all,” he admitted at last. “It will take some time to get the proper people over here—and by then somebody in the Castle might spot the crumpled plane and start to investigate. Time’s more than money now—let’s go.”

“But do you think you can make it?”

“Can do,” he said grimly. “I’ve got a sweet headache, but it might be worse. How about you?”

“Ditto,” she smiled. “Are you going to drag that heavy crowbar?”

“Think it might be wise. Lucky I found it by that camouflaged dump. I had to bash the lock of the door to the main tunnel with it. And there may be another door farther along.”

“Then I’ll take the candle,” she said. With the light held well over her head, she followed him out of the chamber.

The tunnel from here on was concreted, walls, roof and floor. Passing quickly along for possibly a hundred yards, they approached a steep flight of steps. At the top they found a closed door. Bill turned the handle and it swung inward.

“Guess I won’t need this any more,” he said and braced the door open with the crowbar. “If they’re too many for us, we may have to leave in a hurry. Just as well to keep the way clear.”

By the feeble light of the candle they saw that they stood in a small whitewashed cellar. Leading off this to the left, was an open corridor, and from some distance down this passage came the glow of electric light. A large safe, painted white, was built into a corner of the cellar wall.

At a nod from Bill, Dorothy blew out the light and placed the candlestick on the stone floor. Then as she straightened up he brought his lips close to her ear.

“I’ll bet that’s where they keep the loot! Follow me, and hold your gun handy.”

One after the other, on tiptoe, the pair crept across the cellar, their rubber-soled shoes making not the slightest sound. When they came to the corridor, Bill slackened his pace but continued to stalk steadily forward. On their left the whitewashed wall led straight on in an unbroken line. In the right wall, they saw the iron grills of cells. They passed the first, which was dark, and evidently empty. From the second came the glow of light.

Bill turned and placed a finger on his lips. Then he got down on his hands and knees and crawled forward to the door.

“Good heavens!” Dorothy heard him gasp. “So that’s where they had you!”

He stood up and she hurried toward him.

“Terry!”

Her cry was one of absolute amazement. Through the grating she saw her long lost friend, starting up from his cot where he had been reading when Bill’s exclamation caused him to look around. Terry advanced to the door and greeted them.

“Well, by all that’s wonderful! Dorothy! Bill Bolton! What—”

“Are you all right? You’re not hurt or anything?” Dorothy’s excited whisper broke in upon his incoherent surprise.

“No, I’m safe and sound, except that I’m pretty tired of reading—cooped up in this hole. But say, how did you two manage to get down here?”

“Through the tunnel,” replied Bill with a grin.

“Gee, is there a tunnel, too? Never heard of it. How about that lad Peters and the others—you didn’t see them?”

“No, we came through the cellar. Have you any idea where they are?”

“Upstairs, probably—in the house—playing cards. Since Peters came here a few days ago he’s been bringing me my grub. He’s quite chatty; likes to boast about how he trims those others at poker.”

“How many men are there altogether, do you know?” asked Dorothy.

“I’ve never seen more than three at a time, unless you count their be-whiskered pilot I mixed it up with at the beach club. Remember him, Dorothy? But he doesn’t come around much, so Peters says. He doesn’t like him—thinks he’s high-hat.”

“Well, he’s out of the picture, now,” declared Bill. “We got him in the tunnel.”

“Yes—and Terry, do you know that he is Mr. Tracey?” Dorothy could not contain the exciting news any longer.

“Great grief! You don’t say so! I never could stand that fellow—didn’t think he had sense enough to come in out of the rain. But then, you never can tell which way a cat will jump.” He stepped closer to the grill and looked anxiously from Bill to Dorothy. “Say, do you think you two could find a way of getting me out of here?”

“We left a grand crowbar in the cellar! Don’t you think we could bash the lock with it, Bill?”

“Might pry it open. But I’m afraid the noise would give us away—”

“Not a chance of that—if you mean it might disturb the poker players,” Terry interrupted. “There’s a perfect whale of a sound proof door at the head of the stairs. I was brought down that way. They always keep it shut.”

“Good!” Bill hurried off to get the crowbar.

“What’s all this about, Dorothy?” asked Terry. “All I know is that these lads held up my car the night of the Sillies. Some bird in a mask drew a gun on me—my eyes were bandaged and I was popped into another bus and brought over here. Where am I, anyway?”

“Why, you’re in that old stone Castle—near North Stamford. This is a diamond smuggling gang we’re up against. The local and the state police, not to mention Secret Service agents, have been scouring the country for you. Wait till you see the newspapers! You’re nationally famous! But your mother and father and the rest of us have been terribly worried.”

Terry nodded. “I’ve been thinking of that,” he replied. “But diamond smugglers, eh! No wonder—” he whistled softly. “You’ve no idea what it was like to be caged up here—thinking of the family and how terrible it was for them—not knowing why I was here, or if I’d ever be set free. Yet they’ve not tried any rough stuff. Gave me plenty of books and magazines, and enough decent food, thank goodness!”

Bill reappeared, carrying the bar.

“Now get back from the door, Terry,” he cautioned. “I’m going to have a go at it with this.”

He placed the end of the crowbar through the grating and behind the steel disk which held the lock. Then he shoved it forward and sideways until that end was jammed between the inner edge of the door and the frame.

“Lend me a hand, please, Dorothy, and we’ll see what a bit of leverage will do.”

Together they seized the crowbar and pulled. There was a sharp snap and the door flew open.

“Good enough!” cried Terry. He sprang into the corridor and grasped their hands.

“You said it,” laughed Bill. “That’s the second time this bar has come in handy since we started this job. If we ever get out of here I’m going to keep it as a souvenir.”

“I’ll take the diamonds,” Dorothy added enthusiastically.

“What’s on deck now?” inquired Terry.

Bill grew suddenly serious.

“Have you any idea where they keep themselves above?”

“It’s ten to one they’ll be playing poker in the kitchen. They’ve nothing else to do now, except to feed me—or so Peters says.”

“Where’s the kitchen? I mean, how do we get to it from here?”

“It’s along this passage and up the staircase at the end. The door at the top—the sound proof one—opens into the kitchen.”

Bill handed Terry a gun. “Don’t be afraid to use it,” he commanded. “They won’t hesitate to shoot if they get a chance.”

Terry looked at him in great disdain. “Say, just because I appear to be my cheerful self and so on, don’t get the idea that I’ve enjoyed this rest cure. All I’ve been thinking about for days—and nights too—is the chance to get even with them. Now I have it.” He patted the revolver.

“O.K. then, come along, both of you.”

It was but a step to the turn in the passage. Directly ahead lay a steep flight of stairs. And at the top was the silent menace of the closed door.