"We ought to be somewhere near the place now, Tom."

"I think we are, Ned. But you know I'm not going too close in this airship."

"Bless my silk hat!" exclaimed Mr. Damon. "I hope we don't have to walk very far in such a deserted country as this, Tom Swift."

"We'll have to walk a little way, Mr. Damon," replied the young inventor. "If I go too close to the hut they'll see the airship, and as those spies probably know that Mr. Petrofsky has been dealing with me, They'd smell a rat at once, and run away, taking him with them, and we'd have all our work to do over again."

"That's right," agreed Detective Trivett, who was one of the four in the airship that was now hovering over the Atlantic coast, about ten miles below the summer resorts of which Asbury Park was one.

It was only a few hours after Tom had received the letter from Russia informing him of the whereabouts of the kidnapped Russian, and he had acted at once.

His father sanctioned the plan of going to the rescue in one of Tom's several airships and, Mr. Damon, having been on hand, at once agreed to go. Of course Ned went along, and they had picked up the private detective in New York, where he was vainly seeking a clew to the whereabouts of Mr. Petrofsky.

Now the young inventor and his friends were hovering over the sandy stretch of coast that extends from Sandy Hook down the Atlantic seaboard. They were looking for a small fishing hamlet on the outskirts of which, so the Russian letter stated, was situated the lonely hut in which Mr. Petrofsky was held a prisoner.

"Do you think you can pick it out from a distance, Tom?" asked Mr. Damon, as the airship floated slowly along. It was not the big one they intended taking on their trip to Siberia, but it was sufficiently large to accommodate the four and leave room for Mr. Petrofsky, should they succeed in rescuing him.

"I think so," answered the young inventor.

In the letter from Russia a comparatively accurate description of the prisoner's hut had been given, and also some details about his guards. For there is little goes on in political circles in the realm of the Czar that is not known either to the spies of the government or those of the opposition, and the latter had furnished Tom with reliable information.

"That looks like the place," said Tom at length, when, after peering steadily through a powerful telescope, during which time Ned steered the ship, the young inventor "picked up" a fishing settlement. "There is the big fish house, spoken of in the letter," he went on, "and the Russians know a lot about fish. That house makes a good landmark. We'll go down now, before they have a chance to see us."

The others thought this a good idea, and a little later the airship sank to the ground amid a lonely stretch of sand dunes, about two miles from the hamlet on the outskirts of which the prison hut was said to be located.

"Now," said Tom, "we've got to decide on a plan of Campaign. It won't do for all of us to go to the hut and make the rescue. Some one has got to stay with the airship, to be ready to start it off as soon as we come back with Mr. Petrofsky--if we do come.

"Then there's no use in me staying here," spoke Detective Trivett. "I don't know enough even to turn on the gasolene."

"No, it's got to be Ned or me," said the young inventor.

"I'll stay," volunteered Ned quickly, for though he would very much have liked to be in at the rescue, he realized that his place was in the airship, as Mr. Damon was not sufficiently familiar with the machinery to operate it.

Accordingly, after looking to everything to see that it was in working order, Tom led the advance. It was just getting dusk, and they figured on getting to the hut after dark.

"Have everything ready for a quick start," Tom said to Ned, "for we may come back running."

"I will," was the prompt answer, and then, getting their bearings, the little party set off.

They had to travel over a stretch of sandy waste that ran along the beach. Back in shore were a few scattered cottages, and not yet opened for the summer, and on the ocean side was the pounding surf. The hut, as Tom recalled the directions, lay just beyond a group of stunted hemlock trees that set a little way hack from the ocean, on a bluff overlooking the sea. It was not near any other building.

Slowly, and avoiding going any nearer the other houses than they could help, the little party made its way. They had to depend on their own judgement now, for the minor details of the location of the hut could not be given in the letter from Russia. In fact the spies themselves, in writing to their head officers about the matter, had not described the location in detail.

"That looks like it over there," said Tom at last, when they had gone about a mile and a half, and saw a lonely hut with a light burning in it.

Cautiously they approached and, as they drew nearer, they saw that the light came through the window of a small hut.

"Looks like the place," commented the detective.

"We'll have a look," remarked Tom.

He crept up so he could glance in the window, and no sooner had he peered in, than he motioned for the others to approach.

Looking under a partly-drawn curtain, Mr. Damon and Mr. Trivett saw the Russian whom they sought. He was seated at a table, his head bowed on his hands, and in the room were three men. A rifle stood in one corner, near one of the guards.

"They're taking no chances," whispered Mr. Damon. "What shall we do, Tom?"

"It's three to three," replied the young inventor. "But if we can get him away without a fight, so much the better. I think I have it. I'll go up to the door, knock and make quite a racket, and demand admittance in the name of the Czar. That will startle them, and they may all three rush to answer. Mr. Damon, you and the detective will stay by the window. As soon as you see the men rush for the door, smash in the window with a piece of driftwood and call to Mr. Petrofsky to jump out that way. Then you can run with him toward the airship, and I'll follow. It may work."

"I don't see why it wouldn't," declared the detective. "Go ahead, Tom. We're ready."

Looking in once more, to make sure that the guards were not aware of the presence of the rescuing party, Tom went to the front door of the hut. It was a small building, evidently one used by fishermen.

Tom knocked loudly on the portal, at the same time crying out in a voice that he strove to make as deep and menacing as possible:

"Open! Open in the name of the Czar!"

Looking through the window, ready to act on the instant, Mr. Damon and the detective saw the three guards spring to their feet. One remained near Mr. Petrofsky, who also leaped up.

"Now!" called the detective to his companion. "Smash the window!"

The next instant a big piece of driftwood crashed through the casement, just as the two men were hurrying to the front door to answer Tom's summons.

"Mr. Petrofsky! This way!" yelled Mr. Damon, sticking his head in through the broken sash. "Come out! We've come to save you! Bless my putty blower, but this is great! Come on!"

For a moment the exile stared at the head thrust through the broken window, and he listened to Tom's emphatic knocks and demands. Then with a cry of delight the Russian sprang for the open casement, while the guard that had remained near him made a leap to catch him, crying out:

"Betrayed! Betrayed! It's the Nihilists! Look out, comrades!"