Before starting the conclusion of the Blind Spot mystery it may be just as well for the two publicists who are bringing it to the press to follow Hobart Fenton's example and go into a bit of explanation.

The two men who wrote the first two parts were participants, and necessarily writing almost in the present tense. While they could give an accurate and vivid account of their feelings and experiences, they could only guess at what lay in the future, at the events that would unravel it all.

But the present writers have the advantage of working, of seeing, of weighing in the retrospect. They know just where they are going.

The coming of Chick Watson brought new perspective. Hitherto we had been looking into the darkness. Whatever had been caught in the focus of the Spot had become lost to our five senses.

Yet, facts are facts. It was no mere trickery that had caught Dr. Holcomb in the beginning. One by one, men of the highest standards and character had been either victims or witness to its reality and power.

So the coming of Watson may well be set down as one of the deciding moments of history. He who had been the victim a year before was returning through the very Spot that had engulfed him. He was the herald of the great unknown, an ambassador of the infinite itself.

It will be remembered that of all the inmates of the house, Dr. Hansen was the only one who had a personal acquaintance with Watson. One year before the doctor had seen him a shadow—wasted, worn, exhausted. He had talked with him on that memorable night in the cafe. Well he remembered the incident, and the subject of that strange conversation—the secret of life that had been discovered by the missing Dr. Holcomb. And Dr. Hansen had pondered it often since.

What was the force that was pulsing through the Blind Spot? It had reached out on the earth, and had plucked up youth as well as wisdom. THIS was the first time it had ever given up that which it had taken!

It was Watson, sure enough; but it was not the man he had known one year before. Except for the basic features Hansen would not have recognized him; the shadow was gone, the pallor, the touch of death. He was hale and radiant; his skin had the pink glow of alert fitness; except for being dazed, he appeared perfectly natural. In the tense moment of his arrival the little group waited in silence. What had he to tell them?

But he did not see them at first. He groped about blindly, moving slowly and holding his hands before him. His face was calm and settled; its lines told decision. There was not a question in any mind present but that the man had come for a purpose.

Why could he not see? Perhaps the light was too dim. Some one thought to turn on the extra lights.

It brought the first word from Watson. He threw up both arms before his face; like one shutting out the lightning.

“Don't!” he begged. “Don't! Shut off the lights; you will blind me! Please; please! Darken the room!”

Sir Henry sprang to the switch. Instantly the place went to shadow; there was just enough light from the moon to distinguish the several forms grouped in the middle of the room. Dr. Hansen proffered a chair.

“Thank you! Ah! Dr. Hansen! You are here—I had thought—This is much better! I can see fairly well now. You came very near to blinding me permanently! You didn't know. It's the transition.” Then: “And yet—of course! It's the moon! THE MOON!”

He stopped. There was a strange wistfulness in the last word. And suddenly he rose to his feet. He turned in gladness, as though to drink in the mellow flow of the radiance.

“The moon! Gentlemen—doctor—who are these people? This is the house of the Blind Spot! And it is the moon—the good old earth! And San Francisco!”

He stopped again. There was a bit of indecision and of wonder mixed with his gladness. The stillness was only broken by the scarcely audible voice of Mme. Le Fabre.

“Now we KNOW! It is proven. The sceptics have always asked why the spirits work only in the half light. We know now.”

Watson looked to Dr. Hansen. “Who is this lady? Who are these others?”

“Can you see them?”

“Perfectly. It is the lady in the corner; she thinks—”

“That you are a spirit!”

Watson laughed. “I a spirit? Try me and see!”

“Certainly,” asserted Mme. Le Fabre. “You are out of the Blind Spot. I know; it will prove everything!”

“Ah, yes; the Spot.” Watson hesitated. Again the indecision. There was something latent that he could not recall; though conscious, part of his mind was still in the apparent fog that lingers back into slumber.

“I don't understand,” he spoke. “Who are you?”

It was Sir Henry this time. “Mr. Watson, we are a sort of committee. This is the house at 288 Chatterton Place. We are after the great secret that was discovered by Dr. Holcomb. We were summoned by Hobart Fenton.”

Consciousness is an enigma. Hitherto Watson had been almost inert; his actions and manner of speech had been mechanical. That it was the natural result of the strange force that had thrown him out, no one doubted. The mention of Hobart Fenton jerked him into the full vigour of wide-awake thinking; he straightened himself.

“Hobart! Hobart Fenton! Where is he?”

“That we do not know,” answered Sir Henry. “He was here a moment ago. It is almost too impossible for belief. Perhaps you can tell us.”

“You mean—”

“Exactly. Into the Blind Spot. One and the other; your coming was coincident with his going!”

Chick raised up. Even in that faint light they could appreciate the full vigour of his splendid form. He was even more of an athlete than in his college days, before the Blind Spot took him. And when he realised what Sir Henry had said he held up one magnificent arm, almost in the manner of benediction:

“Hobart has gone through? Thank Heaven for that!”

It was a puzzle. True, in that little group there was represented the accumulated wisdom of human effort. With the possible exception of the general, there was not a sceptic among them. They were ready to explain almost anything—but this.

In the natural weakness of futility they had come to associate the aspect of death or terror with the Blind Spot. Yet, here was Watson! Watson, alive and strong; he was the reverse of what they had subconsciously expected.

“What is this Blind Spot?” inquired Sir Henry evenly. “And what do you mean by giving thanks that Fenton has gone into it?”

“Not now. Not one word of explanation until—What time is it?” Watson broke off to demand.

They told him. He began to talk rapidly, with amazing force and decision, and in a manner whose sincerity left no chance for doubt.

“Then we have five hours! Not one second to lose. Do what I say, and answer my questions!” Then: “We must not fail; one slip, and the whole world will be engulfed—in the unknown! Turn on the lights.”

There was that in the personality and the vehemence of the man that precluded opposition. Out of the Blind Spot had come a dynamic quality, along with the man; a quickening influence that made Watson swift, sure, and positive. Somehow they knew it was a moment of Destiny.

Watson went on:

“First, did Hobart Fenton open the Spot? Or was it a period? By 'period' I mean, did it open by chance, as it did when it caught Harry and me? Just what did Hobart do? Tell me!”

It was a singular question. How could they answer it? However, Dr. Malloy related as much as he knew of what Hobart had done; his wires and apparatus were now merely a tangled mass of fused metals. Nothing remained intact but the blue gem and the red pebble.

“I see. And this pebble: you found it by digging in the cellar, I suppose.”

How did he know that? Dr. Hansen brought that curiously heavy little stone and laid it in Watson's hand. The newcomer touched it with his finger, and for a brief moment he studied it. Then he looked up.

“It's the small one,” he stated. “And you found it in the cellar. It was very fortunate; the opening of the Spot was perhaps a little more than half chance. But it was wonderfully lucky. It let me out. And with the help of God and our own courage we may open it again, long enough to rescue Hobart, Harry, and Dr. Holcomb. Then—we must break the chain—we must destroy the revelation; we must close the Spot forever!”

Small wonder that they couldn't understand what he meant. Dr. Hansen thought to cut in with a practical question:

“My dear Chick, what's inside the Spot? We want to know!”

But it was not Watson who answered. It was Mme. Le Fabre.

“Spirits, of course.”

Watson gave a sudden laugh. This time he answered:

“My dear lady, if you know what I know, and what Dr. Holcomb has discovered, you would ask YOURSELF a question or so. Possibly you yourself are a spirit!”

“What!” she gasped. “I—a spirit!”

“Exactly. But there is no time for questions. Afterwards—not now. Five hours, and we must—”

Someone came to the door. It was Jerome. At the sight of Watson he stopped, clutching the stub of his cigar between his teeth. His grey eyes took in the other's form from head to shoe leather.

“Back?” he inquired. “What did you find out, Watson? They must have fed you well over yonder!”

And Jerome pointed toward the ceiling with his thumb. It wasn't in his dour nature to give way to enthusiasm; this was merely his manner of welcome. Watson smiled.

“The eats were all right, Jerome, but not all the company. You're just the man I want. We have little time; none to spare for talk. Are you in touch with Bertha Holcomb?”

The detective nodded.

Watson took the chair that Fenton had so strangely vacated and reached for paper and pencil. Once or twice he stopped to draw a line, but mostly he was calculating. He referred constantly to a paper he took from his pocket. When he was through he spread his palm over what he had written.

“Jerome!”

“Yes.”

“You are no longer connected with headquarters, I presume. But—can you get men?”

“If need be.”

“You will need them!” Just then Watson noticed the uniform of General Hume. “Jerome, can you give this officer a bodyguard?”

It was both unusual and lightning-sudden. Nevertheless, there was something in Watson's manner that called for no challenge; something that would have brooked no refusal. And the general, although a sceptic, was acting solely from force of habit when he objected:

“It seems to me, Watson, that you—”

Those who were present are not likely to forget it. Some men are born, some rise, to the occasion; but Watson was both. He was clear-cut, dominant, inexorable. He levelled his pencil at the general.

“It SEEMS to you! General, let me ask you: If your country's safety were at stake, would you hesitate to throw reinforcements into the breach?”

“Hardly.”

“All right. It's settled. Take care of your red tape AFTERWARDS.”

He wheeled to the detective. “Jerome, this is a sketch of the compartments of Dr. Holcomb's safe. Not the large one in his house, but the small one in his laboratory. Go straight to Dwight Way. Give this note,” indicating another paper, “to Bertha Holcomb. Tell her that her father is safe, and that I am out of the Blind Spot. Tell her you have come to open the laboratory safe. I've written down the combination. If it doesn't work use explosives; there's nothing inside which force can harm. In the compartment marked 'X' you will find a small particle about the size of a pea, wrapped in tin-foil, and locked in a small metal box. You will have to break the box. As for the contents, once you see the stone you can't mistake it; it will weigh about six pounds. Get it, and guard it with your life!”

“All right.”

Jerome put Watson's instructions in his wallet, at the same time glancing about the room.

“Where is Fenton?” he asked.

It was Watson who answered. He gave us the first news that had ever come from the Blind Spot. He spoke with firm deliberation, as though in full realisation of the sensation:

“Hobart Fenton has gone through the Blind Spot. Just now he is right here in this room.”

Sir Henry jumped.

“In this room! Is that what you said, Watson?”

The other ignored him.

“Jerome, you haven't a minute to lose! You and the general; bring that stone back to this house at ANY cost! Hurry!”

In another moment Jerome and Hume were gone. And few people, that day, suspected the purport of that body of silent men who crossed over the Bay of San Francisco. They were grim, and trusted, and under secret orders. They had a mission, did they but know it, as important as any in history. But they knew only that they were to guard Jerome and the general at all hazards. One peculiarly heavy stone, “the size of a pea”! How are we ever to calculate its value?

As for the group remaining with Watson, not one of them ever dreamed that any danger might come out of the Blind Spot. Its manifestations had been local and mostly negative. No; the main incentive of their interest had been simply curiosity.

But apparently Watson was above them all. He paid no further attention to them for a while; he bent at Fenton's desk and worked swiftly. At length he thrust his papers aside.

“I want to see that cellar,” he announced. “That is, the point where you found that red pebble!”

Down in the basement, Sir Henry gave the details. When he came to mention the various liquids which Fenton had poured into the woodwork upstairs Watson examined the pool intently.

“Quite so. They would come out here—naturally.”

“Naturally!”

Sir Henry could not understand. His perplexity was reflected in the faces of Herold, the two physicians, Dr. Malloy, Miss Clarke, and Mme. Le Fabre—and Charlotte spoke for them all:

“Can't you explain, Mr. Watson? The woodwork had nothing whatever to do with the cellar. There was the floor between, just as you see it now.”

“Naturally,” Watson repeated. “It could be no other place! It was on its way to the other side, but it could go only half-way. Simply a matter of focus, you know. I beg pardon; you must hold your curiosity a little longer.”

He began measuring. First he located the line across the floorjoists overhead, where rested the partition separating the dining-room from the parlour. Finding the middle of this line, he dropped an improvised plumb-line to the ground; and from this spot as centre, using a string about ten feet long, he described a circle on the earth. Then, referring to his calculations, he proceeded to locate several points with small stakes pressed into the soil. Then he checked them off and nodded.

“It's even better than the professor thought. His theory is all but proven. If Jerome and Hume can deliver the other stone without accident, we can save those now inside the Spot.” Then, very solemnly: “But we face a heavy task. It will be another Thermopylae. We must hold the gate against an occult Xerxes, together with all his horde.”

“The hosts of the dead!” exclaimed Mme. Le Fabre.

“No; the living! Just give me time, Madame, and you will see something hitherto undreamed of. As for your theory—tomorrow you may doubt whether you are living or dead! In other words, Dr. Holcomb has certainly proved the occult by material means. He has done it with a vengeance. In so doing he has left us in doubt as to ourselves; and unless he discovers the missing factor within the next few hours we are going to be in the anomalous position of knowing plenty about the next world, but nothing about ourselves.”

He paused. He must have known that their curiosity could not hold out much longer. He said:

“Now, just one thing more, friends, and I can tell you everything, while we are waiting for Jerome and the general to return. But first I must see the one who preceded me out of the spot.”

“Ariadne!” from Charlotte, in wonder.

“Ariadne!” exclaimed Watson. He was both puzzled and amazed. “Did you call her—Ariadne?”

“She is upstairs,” cut in Dr. Higgins.

“I must see her!”

A minute or two later they stood in the room where the girl lay. The coverlet was thrown back somewhat revealing the bare left arm and shoulder, and the delicately beautiful face upon the pillow. Her golden hair was spread out in riotous profusion. The other hand was just protruding from the coverlet, and displayed a faint red mark, showing where Hobart's bracelet had been fastened at the moment he disappeared.

Charlotte stepped over and laid her hand against the girl's cheek. “Isn't she wonderful!” she murmured.

But Dr. Higgins looked to Watson.

“Do you know her?”

The other nodded. He stooped over and listened to her breathing. His manner was that of reverence and admiration. He touched her hand.

“I see how it must have happened. Precisely what I experienced, only—” Then: “You call her Ariadne?”

“We had to call her something,” replied Charlotte. “And the name—it just came, I suppose.”

“Perhaps. Anyhow, it was a remarkably good guess. Her true name is the Aradna.”

“THE Aradna? Who—what is she?”

“Just that: the Aradna. She is one of the factors that may save us. And on earth we would call her queen.” Then, without waiting for the inevitable question, Watson said:

“Your professional judgment will soon come to the supreme test, Dr. Higgins. She is simply numbed and dazed from coming through the Spot.” Charlotte had already described to him the girl's arrival. “The mystery is that she was permitted an hour of rationality before this came upon her. I wonder if Hobart's vitality had anything to do with it?”—half to himself. “As for the Rhamda”—he smiled—“he is merely interested in the Spot; that is all. He would never harm the Aradna; he had nothing whatever to do with her condition. We were mistaken about the man. Anyway, it is the Spot of Life that interests us now.”

“The Spot of Life,” repeated Sir Henry. “Is that—”

“Yes; the Blind Spot, as it is known from the other side. It overtops all your sciences, embraces every cult, and lies at the base of all truth. It is—it is everything.”

“Explain!”

Watson turned to the head upon the pillow. He ventured to touch the cheek, with a trace of tenderness in his action and of wistfulness near to reverence. It was not love; it was rather as one might touch a fairy. In both spirit and substance she was truly of another world. Watson gave a soft sigh and looked up at the Englishman.

“Yes, I can explain. Now that I know she is well, I shall tell you all I know from the beginning. It's certainly your turn to ask questions. I may not be able to tell you all that you want to know; but at least I know more than any other person this side of the Spot. Let us go down to the library.”

He glanced at a clock. “We have nearly five hours remaining. Our test will come when we open the Spot. We must not only open it, but we must close it at all costs.”

They had reached the lower hall. At the front door Watson paused and turned to the others.

“Just a moment. We may fail tonight. In case we do, I would like one last look at my own world—at San Francisco.”

He opened the door. The rest hung back; though they could not understand, they could sense, vaguely, the emotion of this strange man of brave adventure. The scene, the setting, the beauty, were all akin to the moment. Watson, stood bareheaded, looking down at the blinking lights of the city of the Argonauts. The moon in a starlit sky was drifting through a ragged lace of cloud. And over it all was a momentary hush, as though the man's emotion had called for it.

No one spoke. At last Watson closed the door. And there was just the trace of tears in his eyes as he spoke:

“Now my friends—” And led the way into the parlour.