"The entire affair is shrouded in mystery," said D'Arnot. "I have it on the best of authority that neither the police nor the special agents of the general staff have the faintest conception of how it was accomplished. All they know, all that anyone knows, is that Nikolas Rokoff has escaped."

John Clayton, Lord Greystoke--he who had been "Tarzan of the Apes"--sat in silence in the apartments of his friend, Lieutenant Paul D'Arnot, in Paris, gazing meditatively at the toe of his immaculate boot.

His mind revolved many memories, recalled by the escape of his arch-enemy from the French military prison to which he had been sentenced for life upon the testimony of the ape-man.

He thought of the lengths to which Rokoff had once gone to compass his death, and he realized that what the man had already done would doubtless be as nothing by comparison with what he would wish and plot to do now that he was again free.

Tarzan had recently brought his wife and infant son to London to escape the discomforts and dangers of the rainy season upon their vast estate in Uziri--the land of the savage Waziri warriors whose broad African domains the ape-man had once ruled.

He had run across the Channel for a brief visit with his old friend, but the news of the Russian's escape had already cast a shadow upon his outing, so that though he had but just arrived he was already contemplating an immediate return to London.

"It is not that I fear for myself, Paul," he said at last. "Many times in the past have I thwarted Rokoff's designs upon my life; but now there are others to consider. Unless I misjudge the man, he would more quickly strike at me through my wife or son than directly at me, for he doubtless realizes that in no other way could he inflict greater anguish upon me. I must go back to them at once, and remain with them until Rokoff is recaptured--or dead."

As these two talked in Paris, two other men were talking together in a little cottage upon the outskirts of London. Both were dark, sinister-looking men.

One was bearded, but the other, whose face wore the pallor of long confinement within doors, had but a few days' growth of black beard upon his face. It was he who was speaking.

"You must needs shave off that beard of yours, Alexis," he said to his companion. "With it he would recognize you on the instant. We must separate here in the hour, and when we meet again upon the deck of the Kincaid, let us hope that we shall have with us two honoured guests who little anticipate the pleasant voyage we have planned for them.

"In two hours I should be upon my way to Dover with one of them, and by tomorrow night, if you follow my instructions carefully, you should arrive with the other, provided, of course, that he returns to London as quickly as I presume he will.

"There should be both profit and pleasure as well as other good things to reward our efforts, my dear Alexis. Thanks to the stupidity of the French, they have gone to such lengths to conceal the fact of my escape for these many days that I have had ample opportunity to work out every detail of our little adventure so carefully that there is little chance of the slightest hitch occurring to mar our prospects. And now good-bye, and good luck!"

Three hours later a messenger mounted the steps to the apartment of Lieutenant D'Arnot.

"A telegram for Lord Greystoke," he said to the servant who answered his summons. "Is he here?"

The man answered in the affirmative, and, signing for the message, carried it within to Tarzan, who was already preparing to depart for London.

Tarzan tore open the envelope, and as he read his face went white.

"Read it, Paul," he said, handing the slip of paper to D'Arnot. "It has come already."

The Frenchman took the telegram and read:

"Jack stolen from the garden through complicity of new servant. Come at once.--JANE."

As Tarzan leaped from the roadster that had met him at the station and ran up the steps to his London town house he was met at the door by a dry-eyed but almost frantic woman.

Quickly Jane Porter Clayton narrated all that she had been able to learn of the theft of the boy.

The baby's nurse had been wheeling him in the sunshine on the walk before the house when a closed taxicab drew up at the corner of the street. The woman had paid but passing attention to the vehicle, merely noting that it discharged no passenger, but stood at the kerb with the motor running as though waiting for a fare from the residence before which it had stopped.

Almost immediately the new houseman, Carl, had come running from the Greystoke house, saying that the girl's mistress wished to speak with her for a moment, and that she was to leave little Jack in his care until she returned.

The woman said that she entertained not the slightest suspicion of the man's motives until she had reached the doorway of the house, when it occurred to her to warn him not to turn the carriage so as to permit the sun to shine in the baby's eyes.

As she turned about to call this to him she was somewhat surprised to see that he was wheeling the carriage rapidly toward the corner, and at the same time she saw the door of the taxicab open and a swarthy face framed for a moment in the aperture.

Intuitively, the danger to the child flashed upon her, and with a shriek she dashed down the steps and up the walk toward the taxicab, into which Carl was now handing the baby to the swarthy one within.

Just before she reached the vehicle, Carl leaped in beside his confederate, slamming the door behind him. At the same time the chauffeur attempted to start his machine, but it was evident that something had gone wrong, as though the gears refused to mesh, and the delay caused by this, while he pushed the lever into reverse and backed the car a few inches before again attempting to go ahead, gave the nurse time to reach the side of the taxicab.

Leaping to the running-board, she had attempted to snatch the baby from the arms of the stranger, and here, screaming and fighting, she had clung to her position even after the taxicab had got under way; nor was it until the machine had passed the Greystoke residence at good speed that Carl, with a heavy blow to her face, had succeeded in knocking her to the pavement.

Her screams had attracted servants and members of the families from residences near by, as well as from the Greystoke home. Lady Greystoke had witnessed the girl's brave battle, and had herself tried to reach the rapidly passing vehicle, but had been too late.

That was all that anyone knew, nor did Lady Greystoke dream of the possible identity of the man at the bottom of the plot until her husband told her of the escape of Nikolas Rokoff from the French prison where they had hoped he was permanently confined.

As Tarzan and his wife stood planning the wisest course to pursue, the telephone bell rang in the library at their right. Tarzan quickly answered the call in person.

"Lord Greystoke?" asked a man's voice at the other end of the line.

"Yes."

"Your son has been stolen," continued the voice, "and I alone may help you to recover him. I am conversant with the plot of those who took him. In fact, I was a party to it, and was to share in the reward, but now they are trying to ditch me, and to be quits with them I will aid you to recover him on condition that you will not prosecute me for my part in the crime. What do you say?"

"If you lead me to where my son is hidden," replied the ape-man, "you need fear nothing from me."

"Good," replied the other. "But you must come alone to meet me, for it is enough that I must trust you. I cannot take the chance of permitting others to learn my identity."

"Where and when may I meet you?" asked Tarzan.

The other gave the name and location of a public-house on the water-front at Dover--a place frequented by sailors.

"Come," he concluded, "about ten o'clock tonight. It would do no good to arrive earlier. Your son will be safe enough in the meantime, and I can then lead you secretly to where he is hidden. But be sure to come alone, and under no circumstances notify Scotland Yard, for I know you well and shall be watching for you.

"Should any other accompany you, or should I see suspicious characters who might be agents of the police, I shall not meet you, and your last chance of recovering your son will be gone."

Without more words the man rang off.

Tarzan repeated the gist of the conversation to his wife. She begged to be allowed to accompany him, but he insisted that it might result in the man's carrying out his threat of refusing to aid them if Tarzan did not come alone, and so they parted, he to hasten to Dover, and she, ostensibly to wait at home until he should notify her of the outcome of his mission.

Little did either dream of what both were destined to pass through before they should meet again, or the far-distant--but why anticipate?

For ten minutes after the ape-man had left her Jane Clayton walked restlessly back and forth across the silken rugs of the library. Her mother heart ached, bereft of its firstborn. Her mind was in an anguish of hopes and fears.

Though her judgment told her that all would be well were her Tarzan to go alone in accordance with the mysterious stranger's summons, her intuition would not permit her to lay aside suspicion of the gravest dangers to both her husband and her son.

The more she thought of the matter, the more convinced she became that the recent telephone message might be but a ruse to keep them inactive until the boy was safely hidden away or spirited out of England. Or it might be that it had been simply a bait to lure Tarzan into the hands of the implacable Rokoff.

With the lodgment of this thought she stopped in wide-eyed terror. Instantly it became a conviction. She glanced at the great clock ticking the minutes in the corner of the library.

It was too late to catch the Dover train that Tarzan was to take. There was another, later, however, that would bring her to the Channel port in time to reach the address the stranger had given her husband before the appointed hour.

Summoning her maid and chauffeur, she issued instructions rapidly. Ten minutes later she was being whisked through the crowded streets toward the railway station.

It was nine-forty-five that night that Tarzan entered the squalid "pub" on the water-front in Dover. As he passed into the evil-smelling room a muffled figure brushed past him toward the street.

"Come, my lord!" whispered the stranger.

The ape-man wheeled about and followed the other into the ill-lit alley, which custom had dignified with the title of thoroughfare. Once outside, the fellow led the way into the darkness, nearer a wharf, where high-piled bales, boxes, and casks cast dense shadows. Here he halted.

"Where is the boy?" asked Greystoke.

"On that small steamer whose lights you can just see yonder," replied the other.

In the gloom Tarzan was trying to peer into the features of his companion, but he did not recognize the man as one whom he had ever before seen. Had he guessed that his guide was Alexis Paulvitch he would have realized that naught but treachery lay in the man's heart, and that danger lurked in the path of every move.

"He is unguarded now," continued the Russian. "Those who took him feel perfectly safe from detection, and with the exception of a couple of members of the crew, whom I have furnished with enough gin to silence them effectually for hours, there is none aboard the Kincaid. We can go aboard, get the child, and return without the slightest fear."

Tarzan nodded.

"Let's be about it, then," he said.

His guide led him to a small boat moored alongside the wharf. The two men entered, and Paulvitch pulled rapidly toward the steamer. The black smoke issuing from her funnel did not at the time make any suggestion to Tarzan's mind. All his thoughts were occupied with the hope that in a few moments he would again have his little son in his arms.

At the steamer's side they found a monkey-ladder dangling close above them, and up this the two men crept stealthily. Once on deck they hastened aft to where the Russian pointed to a hatch.

"The boy is hidden there," he said. "You had better go down after him, as there is less chance that he will cry in fright than should he find himself in the arms of a stranger. I will stand on guard here."

So anxious was Tarzan to rescue the child that he gave not the slightest thought to the strangeness of all the conditions surrounding the Kincaid. That her deck was deserted, though she had steam up, and from the volume of smoke pouring from her funnel was all ready to get under way made no impression upon him.

With the thought that in another instant he would fold that precious little bundle of humanity in his arms, the ape-man swung down into the darkness below. Scarcely had he released his hold upon the edge of the hatch than the heavy covering fell clattering above him.

Instantly he knew that he was the victim of a plot, and that far from rescuing his son he had himself fallen into the hands of his enemies. Though he immediately endeavoured to reach the hatch and lift the cover, he was unable to do so.

Striking a match, he explored his surroundings, finding that a little compartment had been partitioned off from the main hold, with the hatch above his head the only means of ingress or egress. It was evident that the room had been prepared for the very purpose of serving as a cell for himself.

There was nothing in the compartment, and no other occupant. If the child was on board the Kincaid he was confined elsewhere.

For over twenty years, from infancy to manhood, the ape-man had roamed his savage jungle haunts without human companionship of any nature. He had learned at the most impressionable period of his life to take his pleasures and his sorrows as the beasts take theirs.

So it was that he neither raved nor stormed against fate, but instead waited patiently for what might next befall him, though not by any means without an eye to doing the utmost to succour himself. To this end he examined his prison carefully, tested the heavy planking that formed its walls, and measured the distance of the hatch above him.

And while he was thus occupied there came suddenly to him the vibration of machinery and the throbbing of the propeller.

The ship was moving! Where to and to what fate was it carrying him?

And even as these thoughts passed through his mind there came to his ears above the din of the engines that which caused him to go cold with apprehension.

Clear and shrill from the deck above him rang the scream of a frightened woman.