Pratt ran downstairs.

"I didn't want to alarm your uncle," said Armstrong, "but just now, looking through a c.h.i.n.k in the boards, I saw four men coming towards the tower. What are we to do?"

Pratt went to the boarded window and looked out.

"Gradoff and the chauffeur," he said. "The other two I haven't seen before. We might have tackled two; let 'em in and bagged them. But four!--probably armed, like Jensen. It's no go."

"We can only lie low, then, and play for time. The door's a stout piece of timber, and it's not so easy to blow off a bolt as to blow in a lock."

"Don't speak," whispered Pratt, "they're just here."

The handle of the door was turned. Then came a sharp knock. A pause of a few seconds; then a more peremptory knock and Gradoff's voice.

"Jensen!"

The Swede prostrate against the wall wriggled and emitted a low gurgling noise through his gag. The boys glanced at him; he was unable to release his limbs; the sound could not have been heard through the thick door.

A third time Gradoff knocked. He rattled the door-handle, repeated his call, with the addition of sundry violent expletives. The boys remained tensely silent.

The voices without subsided. Conversation was still carried on, but in lower tones.

"Probably they think he is downstairs getting paper," whispered Pratt.

"There's nothing alarming at present."

"But they'll smell a rat if he doesn't soon answer. What then?"

"They may think he has fallen ill or something."

"And then?"

"Well, I can't answer for the intelligence of Gradoff and company, but if I were in his shoes I should either break in the door or send some one round by the tunnel. You see, he can't have the ghost of an idea what has happened. And if his game were discovered, he wouldn't expect to find the place merely closed against him."

"I dare say you're right. But don't you think you had better go through the tunnel and hurry Phil up? We should be in a pretty tight place if Gradoff did send a man or two round, and we found, when we had released your uncle, that the exit at the other end was blocked."

"I don't care about leaving you alone. Suppose they broke in while I was away?"

"Two wouldn't be much better than one against four armed ruffians. And they'd guess that you and Phil had gone to fetch the police, and I fancy they'd be too anxious to save their skins to bother much about me. At any rate, I'll risk it. I think you had better go. In fact, when you meet Phil, why not go and tell Mr. Crawshay how things stand? Phil and I will get your uncle away if it's possible, and though I don't suppose Crawshay could do anything to secure the gang--there's apparently only one policeman--he might 'phone or wire the authorities, and set every one on the qui vive for miles around."

"All right. If I'm going, better go at once, before any one has time to go round by the cottage. I'll consult Phil about your suggestion, and go to Crawshay if he agrees. I wish I had the torch. I shall have to grope my way along the tunnel, but I'll be as quick as I can."

He ran noiselessly down the stairs. The flagstone was upright, as it had been left. He jumped into the cavity, crossed the store-room, entered the tunnel on the farther side, and hurried along as rapidly as the darkness allowed. Now and again he stopped to strike a match and to listen for Warrender's footsteps, but he reached the end without having seen or heard anything of his friend.

By the light of a match he saw that the flagstone was slightly depressed. Then he caught sight of Warrender's electric torch lying on the ground, and was seized with a vague uneasiness. He picked up the torch. Revolving the stone, he heard something slide with a metallic rattle along its surface, and felt a smart blow on one of his feet. He flashed the torch, and saw a hammer and a chisel. Still more uneasy, he clambered up into the cellar, and without lowering the flagstone, climbed on to the staircase.

"You there, Phil?" he called up.

There was no answer. The door at the top was open. He rushed up, ran through the kitchen and the corridor to the front of the cottage, and looked anxiously around. No one was in view.

"What on earth is he doing?" he thought.

It was clear that Warrender had fetched the tools from the motor-boat and returned to the cellar. Why then had he left them there? Where had he gone? What could have interrupted him?

Pratt felt himself on the horns of a painful dilemma. He had now the instruments of his uncle's deliverance; one impulse urged him to hurry with them back to the tower. On the other hand, Warrender's disappearance argued that something untoward had happened, and he was loth to leave the spot without making an attempt to find him. For a few moments he stood in the doorway, weighing the one course against the other. A search for Warrender might prove fruitless, and in any case would take time. Meanwhile affairs at the tower might be developing in a way that would nullify the prime motive that had actuated them all--the release of his uncle. It seemed that this had a paramount claim upon him, and he turned, reluctantly, to retrace his steps to the cellar.

As he pa.s.sed the foot of the staircase to the upper floor, it occurred to him that from the windows there, giving a wider outlook over the surroundings of the cottage, he might see Warrender approaching: perhaps, indeed, as the result of an after-thought, he had made a second visit to the motor-boat. Pratt ran upstairs, and going from room to room, threw a searching glance upon the prospect. Neither on the eastern side nor on the western was there anything to attract his attention.

But looking out of the window of the room facing south, he noticed that the foliage of the thicket beyond the weedy path was violently disturbed. Some one was moving in it, towards the ruins. He watched eagerly: surely it was Warrender returning. Presently two legs came into view; but they were not Warrender's. They were encased in rusty brown leggings. In another moment the figure of Rush emerged from the thicket upon the path, and immediately behind him was a second form, that of a tall and heavily built man with a broad flattish face. When free from the thicket they quickened their pace.

Pratt hesitated no longer. The men were evidently making for the ruins: perhaps they intended to proceed along the tunnel. It was imperative that he should antic.i.p.ate them. He hastened downstairs, and had just reached the cellar when he heard clumping footsteps overhead. Leaping into the cavity, he swung the stone over, turned the hand-grips, and by the light of the torch bolted along the tunnel. After running about twenty yards he switched off the light and stopped. Voices came from behind him; then he heard two heavy thuds in succession; the men had jumped into the tunnel. The flagstone banged as it was swung carelessly into place; the men were coming after him. Without more delay he set forward with all speed, guiding himself by touching the walls with his outstretched hands.

CHAPTER XXI

TRAPPED

Meanwhile, what had happened to Warrender?

On entering the cottage by way of the tunnel and the cellar, he went upstairs to make a careful survey of the surroundings, saw no sign of the enemy, and hurried across the island to the pram, in which he crossed the river un.o.bserved. In less than ten minutes he was back at the cottage with the hammer and chisel taken from his motor-boat. As he was on the point of re-opening the trap, he found that the electric torch showed a much feebler light than before, and if it gave out before Mr. Pratt was brought away, the flight through the tunnel might be dangerously delayed. It seemed worth while to pay another rapid visit to the camp for the purpose of getting a small hand lamp or a couple of candles. Laying the hammer and chisel under the staircase, he went up again, once more crossed the island, found one candle in the motorboat, and returned without delay.

It happened, however, that as he left the cottage on this second journey, Rush and his big flat-faced companion were approaching it from the south. Unseen themselves, they caught sight of Warrender as he emerged from the entrance, watched him until he had disappeared into the thicket, waited a few minutes, then entered the cottage and descended to the cellar. They had no light, and Warrender had taken the precaution of carefully replacing the flagstone; but in his haste he had omitted to close the upright slab beneath the lowest step, leaving open the access to the handgrips. Rush was suspicious. The gap might have been left open, of course, by one of the confederates; on the other hand, it was possible that the secret pa.s.sage had been discovered by the boy he had seen leaving the cottage. The boy might return, and Rush allowed his curiosity to delay the visit to the tower on which he had been summoned.

It was an error of judgment that had important consequences.

He posted himself with his companion in a remote corner of the cellar, and waited.

Some ten minutes later, Warrender came down the steps. He flashed his torch to light the opening, retrieved the hammer and chisel, and laid them down on the flagstone while he inserted his arm in the gap to turn the hand-grips. All the time his back was towards the men lurking within twenty feet of him. As he sprawled over the stone, there was a sudden noise behind him. Hastily withdrawing his hand, he half rose, but too late. Seized by powerful hands and taken at a disadvantage, he was helpless. His torch fell into the gap, and in the darkness he was dragged up the stairs between his captors.

"Cotched 'en!" chuckled Rush, as they lugged him through the hall.

"What'll we do with 'en, Sibelius?"

"Kill!" said the Finn. "Throw in river!"

"No, no, that won't do!" said Rush. "He bain't alone. There's the other young devils. It bain't safe. I think of my neck. No; we'll take 'en down to the hut and tie 'en up; he'll be out of harm's way there, and in a few hours it won't matter."

Like most Englishmen in speaking to a foreigner, he shouted, and the Finn warned him to speak more quietly: the prisoner would hear all he said.

"What do it matter?" laughed Rush. "Let 'en hear--by the time his friends find 'en we'll be far away. Curious 'tis, that we've cotched 'en the very last day. If it'd a been yesterday, we might have _had_ to kill 'en. We'll stuff up his mouth, though; t'others may be about."

Pulling Warrender's handkerchief from his pocket, he rolled it up, and thrust it between the lad's teeth. Warrender ruefully reflected that just in such a way had Jensen been gagged that morning. Then the men hauled him through the thicket towards the point of the island where Rush moored his boat.

"I say, Sibelius," remarked Rush, when they were half-way there, "I reckon we'd better not take 'en to the hut after all. 'Twill take time, and we don't know where his mates be. Better go and tell the boss all about it; he'd be fair mad if anything spoilt his game the last moment."

"What we do, then?" asked the Finn.

"We'll truss 'en up: plenty of rope in the boat; and put 'en in among the bushes. He'll be snug enough there."

He chuckled. Dismayed at the prospect opened before him, Warrender, who had hitherto offered no resistance, made a sudden dive towards the ground, at the same time throwing out his leg in an attempt to trip the bulkier of his captors. But though he succeeded in freeing one arm, and causing the Finn to stumble, he had no time to wrench himself from Rush's grip before the other man had recovered his balance and seized him in a clutch of iron.