Farrington and Dr. Fall were closeted together in the latter's office. Something had happened, which was responsible for the gloom on the face of the usually imperturbable doctor, and for the red rage which glowered in the older man's eyes.

"You are sure of this?" he asked.

"Quite sure," said Dr. Fall briefly; "he is making every preparation to leave London. His trunks went away from Charing Cross last night for Paris. He has let his house and collected the rent in advance, and he has practically sold the furniture. There can be no question whatever that our friend has betrayed us."

"He would not dare," breathed Farrington.

The veins stood out on his forehead; he was controlling his passionate temper by a supreme effort.

"I saved this man from beggary, Fall; I took the dog out of the gutter, and I gave him a chance when he had already forfeited his life. He would not dare!"

"My experience of criminals of this character," said Dr. Fall calmly, "is that they will dare anything. You see, he is a particularly obnoxious specimen of his race; all suaveness, treachery, and remorseless energy. He would betray you; he would betray his own brother. Did he not shoot his father—or his alleged father, some years ago? I asked you not to trust him, Farrington; if I had had my way, he would never have left this house."

Farrington shook his head.

"It was for the girl's sake I let him go. Yes, yes," he went on, seeing the look of surprise in the other's face, "it was necessary that I should have somebody who stood in fear of me, who would further my plans in that direction. The marriage was necessary."

"You have been, if you will pardon my expressing the opinion," said Dr. Fall moodily, "just a little bit sentimental, Farrington."

The other turned on him with an oath.

"I want none of your opinions," he said gruffly. "You will never understand how I feel about this child. I took her from her dead father, who was one of my best friends, and I confess, that in the early days the thought of exploiting her fortune did occur to me. But as the years passed she grew towards me—a new and a beautiful influence in life, Fall. It was something that I had never had before, a factor which had never occurred in my stormy career. I grew to love the child, to love her more than I love money, and that is saying a lot. I wanted to do the right thing for her, and when my speculations were going wrong and I had to borrow from her fortune I never had any doubt but what I should be able to pay it back. When all the money went,"—his voice sank until it was little more than a whisper,—"and I realized that I had ruined the one human being in the world whom I loved, I took the step which of all my crimes I have most regretted. I sent George Doughton out of the way in order that I might scheme to marry Doris to the Tollington millionaire. For I knew the man we were seeking was Doughton. I killed him," he said defiantly, "for the sake of his son's wife. Oh, the irony of it!" He raised his hand with a harsh laugh. "The comedy of it! As to Poltavo," he went on more calmly, "I let him go because, as I say, I wanted him to further my object. That he failed, or that he was remiss, does not affect the argument. Doris is safely married," he mused; "if she does not love her husband now, she will love him in time. She respects Frank Doughton, and every day that passes will solidify that respect. I know Doris, and I know something of her secret thoughts and her secret wishes. She will forget me,"—his voice shook,—"please God she will forget me."

He changed the subject quickly.

"Have you heard from Poltavo this morning?"

"Nothing at all," said Fall; "he has been communicating with somebody or other, and the usual letters have been passing. Our man says that he has a big coup on, but upon that Poltavo has not informed us."

"If I thought he was going to play us false——"

"What would you do?" asked Fall quietly. "He is out of our hands now."

There was a little buzz in one corner of the room, and Fall turned his startled gaze upon the other.

"From the signal tower," he said. "I wonder what is wrong."

High above the house was one square solitary tower, in which, day and night, a watcher was stationed. Fall went to the telephone and took down the receiver. He spoke a few words and listened, then he hung up the receiver again and turned to Farrington.

"Poltavo is in Great Bradley," he said; "one of our men has seen him and signalled to the house."

"In Great Bradley!" Farrington's eyes narrowed. "What is he doing here?"

"What was his car doing here the other day," asked Fall, "when he kidnapped Frank Doughton? It was here to throw suspicion on us and take suspicion off himself, the most obvious thing in the world."

Again the buzzer sounded, and again Fall carried on a conversation with the man on the roof in a low tone.

"Poltavo is on the downs," he said; "he has evidently come to meet somebody; the look-out says he can see him from the tower through his glasses, and that there is a man making his way towards him."

"Let us see for ourselves," said Farrington.

They passed out of the room into another, opened what appeared to be a cupboard door, but which was in reality one of the innumerable elevators with which the house was furnished, and for the working of which the great electrical plant was so necessary.

They stepped into the lift, and in a few seconds had reached the interior of the tower, with its glass-paned observation windows and its telescopes. One of the foreign workmen, whom Farrington employed, was carefully scrutinizing the distant downs through a telescope which stood upon a large tripod.

"There he is," he said.

Farrington looked. There was no mistaking Poltavo, but who the other man was, an old man doubled with age, his white beard floating in the wind, Farrington could not say; he could only conjecture.

Dr. Fall, searching the downs with another telescope, was equally in the dark.

"This is the intermediary," said Farrington at last.

They watched the meeting, saw the exchange of the letters, and Farrington uttered a curse. Then suddenly he saw the other leap upon Poltavo and witnessed the brief struggle on the ground. Saw the glitter of handcuffs and turned with a white face to the doctor.

"My God!" he whispered. "Trapped!"

For the space of a few seconds they looked one at the other.

"Will he betray us?" asked Farrington, voicing the unspoken thoughts of Fall.

"He will betray us as much as he can," said the other. "We must watch and see what happens. If he takes him into town, we are lost."

"Is there any sign of police?" asked Farrington.

They scanned the horizon, but there was no evidence of a lurking force, and they turned to watch T. B. Smith and his prisoner making their slow way across the downs. For five minutes they stood watching, then Fall uttered an exclamation.

"They are going to the cottage!" he said, and again the men's eyes met.

"Impossible," said Farrington, but there was a little glint in his eye which spoke of the hope behind the word.

Again an interval of silence. Three pairs of eyes followed the men.

"It is the cottage!" said Fall. "Quick!"

In an instant the two men were in the lift and shooting downwards; they did not stop till they reached the basement.

"You have a pistol?" asked Farrington.

Fall nodded. They quitted the lift and walked swiftly along a vaulted corridor, lighted at intervals with lamps set in niches. On their way they passed a door made in the solid wall to their left.

"We must get her out of this, if necessary," said Farrington in a low voice. "She is not giving any trouble?"

Dr. Fall shook his head.

"A most tactful prisoner," he said, dryly.

At the end of the corridor was another door. Fall fitted a key and swung open the heavy iron portal and the two men passed through to a darkened chamber. Fall found the switch and illuminated the apartment. It was a little room innocent of windows, and lit as all the rest of the basement was by cornice lamps. In one corner was a grey-painted iron door. This Fall pushed aside on its noiseless runners. There was another elevator here. The two men stepped in and the lift sunk and sunk until it seemed as though it would never come to the end. It stopped at last, and the men stepped out into a rock-hewn gallery.

It was easy to see that this was one of the old disused galleries of the old mine over which the house was built. Fall found the switch he sought and instantly the corridor was flooded with bright light.

On a set of rails which ran the whole length of the gallery to a point which was out of sight from where they stood, was a small trolley. It was unlike the average trolley in that it was obviously electrically driven. A third rail supplied the energy, and the controlling levers were at the driver's hand.

Farrington climbed to the seat, and his companion followed, and with a whirr of wheels and a splutter of sparks where the motor brush caught the rail, the little trolley drove forward at full speed.

They slowed at the gentle curves, increased speed again when any uninterrupted length of gallery gave them encouragement, and after five minutes' travel Farrington pulled back the lever and applied the brake. They stepped out into a huge chamber similar to that which they had just left. There was the inevitable lift set, as it seemed, in the heart of the rock, though in reality it was a bricked space. The two men entered and the lift rose noiselessly.

"We will go up slowly," whispered Fall in the other's ear; "it will not do to make a noise or to arouse any suspicions; we must not forget that we have T. B. Smith to deal with."

Farrington nodded, and presently the lift stopped of its own accord. They made no attempt to open whatever door was before them. They could hear voices: one was T. B.'s, and the other was unmistakably Poltavo's, and Poltavo was speaking.

Poltavo was offering in his eager way to betray the men who sat in the darkness listening to his treachery. They heard the motor-car's arrival outside, and presently T. B.'s voice announcing his temporary retirement. They heard the slam of the door, and the key click in the lock, and then Dr. Fall stepped forward, pressed a spring in the rough woodwork in front of him and one of the panels of the room slid silently back.

Poltavo did not see his visitors until they stood over him, then he read in those hateful faces which were turned toward him an unmistakable forecast of his doom.

"What do you want?" he almost whispered.

"Do not raise your voice," said Farrington in the same tone, "or you are a dead man." He held the point of a knife at the other's throat.

"To where are you taking me?" asked Poltavo, ghastly white of face and shaking from head to foot.

"We are taking you to a place where your opportunity for betraying us will be a mighty small one," said Fall.

There was a horrible smile on his thin lips, and Poltavo, with a premonition of what awaited him beyond the tunnel, forgot the menacing knife at his throat and screamed.

Hands gripped him and strangled the cry as it escaped him. Something heavy struck him behind the ear and he lost consciousness. He awoke to find himself travelling smoothly along the rock gallery. He was half lying, half reclining on Fall's knees. He did not attempt to move; he knew now that he was in mortal peril of his life. No word was spoken when he was dragged roughly from the car, placed in another elevator and whirled upwards, emerging into a little chamber at the end of the underground corridor which ran beneath the Secret House.

A door was opened and he was thrust in without a word. He heard the clang of the steel door behind him, and the lights came on to show him that once again he was in the underground room where he had been confined before.

There was the table, there was the heavy chair, there in the far corner of the room was the barred entrance to the other elevator. Anyway he was free from the police; that was something. He was safe just so long as it suited the book of Farrington and his friend to keep him safe. What would they do? What excuse could he offer? They had overheard the conversation between himself and T. B., he knew that, and cursed his folly. He ought to have kept away from Moor Cottage. He knew there was something sinister about the place, but T. B. should have known that even better than he. Why had T. B. left him?

These and a thousand other thoughts shot through his mind as he paced the vaulted apartment. They were in no hurry to feed him. He had almost forgotten what time it was; whether it was day or night in that underground vault into which no ray of sunlight ever penetrated. They had left him with the handcuffs on his wrists; they would come and relieve him of these encumbrances. What were their plans with him? He felt his pockets carefully. T. B. had taken away the only weapon he had had, and for the first time for many years Count Poltavo was unarmed.

His heart was beating with painful rapidity and his breath came laboriously. He was terror-stricken. He turned to find the door through which he had come, and to his surprise he could not see it. So far as he could detect, the stone wall ran without a break from one end of the apartment to the other. Escape could not lie that way; of that he was satisfied. There was nothing to do but to wait, with whatever patience he could summon, to discover their plans. He did not doubt that he was to suffer. He had forfeited all right to their confidence, but if this was to be the only consequence of his ill-doing he was not greatly worried. Count Poltavo, as he had boasted before in this identical room, had been in some tight corners and had faced death in many strange and terrible guises, but the inevitability of doom was never so impressed upon his mind as it was at this moment when he lay guarded by a hundred secret forces in the tomb of the Secret House.

He had one hope, a faint one, that T. B. would discover the method of his exit from the room in Moor Cottage and would track him here.

Evidently the occupants of the Secret House had the same fear, for even here, in the quietness of his underground prison, Poltavo could hear strange whining noises, rumbling, and groaning and grinding, as though the whole of the house were changing its construction.

He had not long to wait for news. A corner lift came swiftly down and Fall stepped briskly towards his prisoner.

"T. B. Smith is in the house," he said, "and is making an inspection; he will be down here in a moment. In these circumstances I shall have to betray one of the secrets of this house." He caught the other roughly by the arm and half led, half dragged, him to a corner of the room. Handcuffed as he was, Poltavo could offer no resistance. Dr. Fall apparently only touched one portion of the wall, but he must have moved, either with his foot or with his hand, some particularly powerful spring, for a section of the stone wall swung backwards revealing a black gap.

"Get in there," said Fall, and pushed him into the darkness.

A few moments later T. B. Smith, accompanied by three detectives, inspected the room which Poltavo had left. There was no sign of the man, no evidence of his having so recently been an occupant of his prison house. For an interminable time Poltavo stood in the darkness. He found he was in a small cell-like apartment with apparently no outlet save that through which he had come.

He was able to breathe without difficulty, for the perfect system of ventilation throughout the dungeons of the Secret House had been its architect's greatest triumph.

It seemed hours that he waited there, though in reality it was less than twenty minutes after his entrance that the door swung open again and he was called out.

Farrington was in the room now, Farrington with his trusty lieutenant, and behind them the one-eyed Italian desperado whom Poltavo remembered seeing in the power house one day, when he had been allowed the privilege of inspection.

Some slight change had been made in the room since he was there last. Poltavo's nerves were in such a condition that he was sensitive to this variation. He saw now what the change was. The table had been drawn back leaving the chair where it was fixed.

Yes, it was a fixed chair, he remembered that and wondered why it had been screwed to the wood block floor. Dr. Fall and the engineer grasped him roughly and hurried him across the room, thrusting him into the chair.

"What are you going to do?" asked Poltavo, white as death.

"That you shall see."

Deftly they strapped him to the chair; his wrists and elbows were securely fastened to the arms, and his ankles to the legs of the massive piece of furniture.

From where he sat Poltavo confronted Farrington, but the big man's mask-like face did not move, nor his eyes waver as he surveyed his treacherous prisoner. Then Fall knelt down and did something, and Poltavo heard the ripping and tearing of cloth.

They were slitting up each trouser leg, and he could not understand why.

"Is this a joke?" he asked with a desperate attempt at airiness.

No reply was made. Poltavo watched his captors curiously. What was the object of it all? The two men busy at the chair lifted a number of curious-looking objects from the floor; they clamped one on each wrist, and he felt the cold surface of some instrument pressing against each calf. Still he did not realize the danger, or the grim determination of these men whose secret he would have betrayed.

"Mr. Farrington," he appealed to the big man, "let us have an understanding. I have played my game and lost."

"You have indeed," said Farrington.

They were the first words he had spoken.

"Give me enough to get out of the country," Poltavo appealed, "just the money that I have in my pocket, and I promise you that I will never trouble you again."

"My friend," said Farrington, "I have trusted you too long. You forced yourself upon me when I did not desire you, you thwarted me at every turn, you betrayed me whenever it was possible to betray me, or whenever it was to your advantage to do so, and I am determined that you shall have no other chance of doing me an injury."

"What is this foolery?" asked Poltavo, in a mixture of blind fear and rage. They had unlocked the handcuffs and taken them off him, and now for the first time Poltavo noticed that the curious bronze clamps on his wrists were attached by thick green cords to a plug in the wall.

He shrieked aloud as he saw this, and the full horror of the situation flashed upon him.

"My God," he screamed, "you are not going to kill me?"

Farrington nodded slowly.

"We are going to kill you painlessly, Poltavo," he said. "It was your life or ours. We do not desire to cause you unnecessary suffering, but here is the end of the adventure for you, my friend."

"You are not going to electrocute me?" croaked the man in the chair, in a hoarse cracked voice. "Don't say that you are going to electrocute me, Farrington! It is diabolical, it is terrible. Give me a chance of life! Give me a pistol, give me a knife, but fight me fair. Treat me as you will; hand me to the police, anything but this; for God's sake, Farrington, don't do this!"

The doctor reached down and lifted a leather helmet from the floor and placed it gently over the doomed man's head.

"Don't do it, Farrington." Poltavo's muffled voice came painfully from behind the leather screen. "Don't! I swear I will not betray you."

Farrington made a little signal and the doctor walked to the wall and placed his hand upon a black switch.

"I will not betray you," said the man in the chair in hollow tones. "Give me a chance. I will not tell them anything that you——"

He did not speak again, for the black switch had been pressed down and death came with merciful swiftness.

They stood watching the figure. A slight quivering of the hands and then Farrington nodded and the doctor turned the switch over again.

Rapidly they unfastened the straps, and the limp thing which was once human, with a brain to think and a capacity for life and love, slipped out of the chair in an inanimate heap upon the ground.

So passed Ernesto Poltavo, an adventurer and a villain, in the prime of his life.

Farrington looked down upon the body with sombre eyes and shrugged his shoulders.

He had opened his mouth to speak and Fall had walked to the switchboard and was about to put the deadly apparatus out of gear, when a sharp voice made them both turn.

"Hands up!" it said.

The stone door, through which Poltavo had passed to his doom from the corridor without, was wide open, and in the doorway stood T. B. and a little behind him Ela, and in T. B.'s hand was a pistol.