Shadows advanced through the shadowy fog, and Garth could define them as no more than shadows. In one place the mist thinned momentarily, and he glimpsed, apparently floating forward, the trunk of a man's figure. Pallid tatters, such as might survive in a mortuary, flapped about bare shoulders, and from a little distance beyond came a sickly gleam—the doubtful response uncertain moonlight might draw from a bayonet or a musket barrel.

The fog closed in. There were no more shadows. Garth, eager to follow, forced himself to wait. He told himself that the march of phantoms possessed a meaning which would give direction to his task. The unveiling of its impulse, he was confident, would unveil the mystery at the house. Against so many only caution was useful at present.

He was glad Nora was not with him. He knew how profoundly she would have been stirred, how ready she would have been to discard a rational explanation for the occult. He could smile a little. In this one respect of vulnerability to superstition he felt himself immeasurably her superior. He was glad she had not involved herself in such a case.

Finally, phantom-like himself, he proceeded through the fog in the direction the silent shadows had taken. He walked for some distance.

Without warning he stumbled and pitched forward to his knees. Reaching out to save himself, his fingers touched something wet, cold, and possessed of a revealing quality which in one breathless moment drove into his brain the excuse for those at the house, and focussed for him their terror of the unexplored world of whose adjacence their solitude must have convinced them.

He snatched his hand back, rendered for the moment without purpose by this silent and singular tryst to which chance had led him in the evil forest. It was necessary, however, to strip the mask of night from the face of the one who lay, defeated and beyond resistance, in the path of the shadowy army.

He took his pocket lamp from his coat and pressed the control. The light fought through the fog to the face of the old servant who a few hours ago had begged him to get Mrs. Alden away, whose lips had been incomprehensibly sealed.

Quickly he searched for the manner of death, for there could be no coincidence about two such catastrophes in the same spot. In spite of the coroner's verdict, murder was the only sensible deduction. Yet he found no slightest souvenir of violence. The face alone held a record of an attack—the features were twisted as if from its vehemence, and the eyes appeared to secrete some shocking vision.

Garth sprang to his feet. Alden's sick fear and his wife's hysterical misgivings were placed on a basis far sounder than imagination. A danger, unconformable, but none the less real, skirted their isolated house, had at last, according to the woman, forced an entrance.

Garth knew his limitations. He must have help, and now Alden must be made to talk.

He ran back to the house and stepped through the window. The lamp had been lighted. It shone on Mrs. Alden who bent over the writing-table, her gaze directed hypnotically towards the huddled man in the chair. Garth, since he came from the rear, could not see Alden's face at first.

"Mrs. Alden," he said, "I found your man, out there—"

Her hands left the table. She straightened. With a perceptible effort she raised her eyes from the chair to meet Garth's.

"Not de—"

She put her hand to her mouth and crushed back the word.

Garth nodded.

"I must have help. Where's the telephone?" he asked.

He started for the hall.

"Lock that window," he said. "I've left it open."

Suddenly he paused and turned. A sound, scarcely human, had come from the chair—a hollow, a meaningless vocal attempt, as though there were no palate behind it, no tongue to shape its intention.

From where he stood Garth could see Alden distinctly enough. His head was sunk forward on his chest. His fingers clutched powerlessly at the chair arms. His eyes appeared to have hoarded and just now released all the strength of which his meager body had been stripped. They flashed with a passionate purpose which drew Garth magnetically until he was close and had stooped and was staring into them with a curiosity almost as pronounced as their eagerness.

"What is it, Mr. Alden?" he asked.

The other's fingers continued to stray about the chair arms.

"You've got to tell me what you know—all you suspect," Garth urged. "We've murder on our hands. What do you know?"

Alden's head rose and fell affirmatively.

"Out with it."

But Alden did not answer, although his eyes burned brighter; and Garth guessed.

"Speak, Mr. Alden," he begged.

Alden's lips moved. His throat worked. His face set in a grotesque grimace.

"There's danger for all of us," Garth cried. "The time for silence has passed."

Then Alden answered, but it was only with that helpless, futile sound—such a whimper as escapes unintelligibly from the fancied fatality of a nightmare.

Garth drew back. Now when it was too late Alden wanted to talk. Now when he had been robbed of the power he craved the abandonment of words.

"Mrs. Alden," Garth whispered. "You know your husband can't speak! Look at him!"

About her advance there was that hypnotic quality Garth had noticed before. He read in her face, moreover, a sympathy and a love that made it as difficult of unmoved contemplation as the helpless suffering in Alden's.

Alden smiled sorrowfully as his wife came close and stooped to him. His hands ceased their straying about the chair arms. They rose with a quick motion, an unsuspected strength, and closed about her white and beautiful throat.

She did not cry out. Perhaps there was no time. Her eyes closed. Her lips were wistful.

Garth tore at the man's fingers. It took all his force to break their hold. And as he fought the answer to a great deal came to him. Alden was clearly insane, and his wife's fear and John's doubt of her safety were accounted for. Yet it didn't answer all. What was the share of the shrouded army in the forest? What was the connection of the death that had struck there twice?

Alden's vise-like grip was broken. Mrs. Alden swayed against the writing-table, gasping. Alden's whimpering had recommenced.

Garth looked from one to the other.

"Good God!" he said.

She turned on him.

"Why did you come? It is your fault."

Garth pointed at the cabinet where the medicine was kept. The nightmare whimpering did not cease.

"Get him something," Garth directed. "The doctor must have left you a narcotic."

She walked with a pronounced lurch to the cabinet where Garth heard her fumbling among the bottles, but he did not turn away from Alden. The imbecile sounds stopped, but the lips worked ineffectively again. One of the hands moved slowly with an apparent sanity of purpose. Garth realized that it was motioning him back. Alden started to rise. Garth saw his veins swell and the emaciated muscles strain as he literally dragged himself out of the chair and braced his elbows against the writing-table. He grasped a pencil and wrote rapidly on a piece of paper. Garth understood, and he reached out for the sheet on which Alden had written the words—perhaps a warning, perhaps the truth—which his tongue had been unable to form.

"Don't touch that paper."

There was a new quality about the voice Garth could not deny. There was no more tinkling of glass at the cabinet. He found it difficult to credit Mrs. Alden with that clear, authoritative command. He turned warily and looked into the muzzle of his own revolver. Mrs. Alden's outstretched hand, he noticed, did not waver.

"What does this mean?" he cried.

"It means," she answered in a tired voice, "that if you read what is on that paper you'll leave me no choice. I shall have to shoot."

Alden whimpered again. The paper fluttered to the floor and rested, white and uncommunicative, beneath the table. His face set. He pointed accusingly towards the rear window.

The gesture was clear to Garth. He knew what it meant before his eyes followed its direction. Before he had seen, he appreciated almost palpably the new presence in the room. At the moment it seemed inevitable to him that the tense group should be joined by a stronger force, the inspiration, probably, of the mysteries that had posed it, and that worked ahead, he could not doubt, to a graver issue for Alden and himself.

The newcomer glided from the shadows by the window and moved to Mrs. Alden's side—huge, powerful. The cap, drawn low over his eyes, and the thick growth about the mouth, robbed his face of expression and gave to his actions a mechanical precision not lightly to be disturbed. He took the revolver from the woman.

"I couldn't," she said. "He hasn't read. It won't be necessary?"

"Necessary," the man answered, "but you were right. Not in that way. It leaves too much evidence. As the others went."

"No more death," she cried. "There has been too much death."

"These days the world is full of death," he answered. "What are one or two here?"

The voice carried as little expression as the face or the figure, but an accent, which Garth knew, hindered its flow, and defined the situation with a brutal clearness.

He turned at a slipping behind him, a heavy fall. Alden lay on the floor, his hand stretched towards the futile spot of white beneath the table. His wife stumbled across and knelt beside him, restlessly fingering his shoulders.

"Andrew!" she cried. "You don't understand. Look at me. You have to understand. I love you. Nothing changes that."

The newcomer moved to her, and, without relaxing his vigilance, grasped her arm.

"There's too much to be done to-night for tears. Keep your watch."

He indicated Garth.

"I'll come back and attend to him later."

She continued to stare at her husband's closed eyes.

"He knows now, but you shan't kill him. I tell you you shan't kill him."

"When the occasion arises you will follow your duty," he said.

He turned to Garth, pointing to the oak door in the rear corner.

"You will go in there."

A flashing recollection of Nora decided Garth. Resistance now, he knew, as he studied the great figure, would mean the end, whereas, if he waited and obeyed, the knife, secreted in his felt, offered a possible escape.

"Wait!" the man snapped.

He thrust the revolver in Mrs. Alden's hand while he ran quickly over Garth's clothing. The thickness of the belt escaped him. He found only the pocket lamp.

"The telephone is disconnected," he said, evidently to reassure the woman. "Your husband is too weak to leave the house, and no one will come near it until daylight. We won't cross that bridge before we reach it."

She shuddered.

The other opened the oak door and motioned Garth to enter. He went through, simulating a profound dejection, but actually reaching out again to confidence. For the man would come back to visit him with the silent, undemonstrative violence that had done for the two men in the woods, but Garth would be waiting for him, behind the door, with his knife. Therefore, when the door was locked, he commenced hopefully to examine his prison.

The night, he found after a moment, was not complete in here. It possessed a quality, milky but lustreless, reminiscent of the shroud through which the shadowy figures had paraded. It retained, however, the obscurity of thorough darkness. He had a feeling, indeed, of standing in a darkness that was white.

There must be windows over there, many windows. He felt his way across. The wall, as well as the interior face of the door, was lined with sheet tin, suggesting immediately the nature of his prison—a dismantled conservatory. The glazed end was of small panes, heavily leaded. The frames in themselves offered a resistance to escape as efficacious as prison bars.

The arrangement, nevertheless, gave him one advantage. A single door to guard removed the threat of a surprise.

In the centre of the floor he found a considerable heap of wood, probably the fittings of the place. He scarcely dared pause to examine it. He hurried back to his post at the doorway, removed the knife from his belt, jointed it, and tested the point against his finger. He didn't know how long his respite would last. He couldn't hazard a guess as to the nature of the big man's occupation. He could only estimate its importance by the fact that it had prevented the other's dealing summarily with him.

He had entered the case with too little light. Nora had been right. One can not follow a straight course through the dark. Only a few dim outlines offered themselves for his appraisal. Mrs. Alden had made her choice between an evident, an exceptional affection for her husband and an enterprise directed by the sinister figure who had stepped from the shadows. Of what a vast importance that enterprise must be since it had prodded her to such a decision, since it had made her acquiesce, however unwillingly, in murder to safeguard its progress! She faced even the death of her own husband because he had learned too much of its intention. And she had no slightest amorous tendency—of that Garth was sure—towards the bearded giant to whose will she bent her own with a pitiable humility. The lack of that world-wide, easily comprehensible motive to wrong, taken with the leader's German accent, directed Garth's logic to the furnaces, which night after night stained the sky with a scarlet, significant of their feverish industry. Yet the shadowy figures of the woods were still elusive, unless the place was used as a rendezvous and the affair to-night approached a crisis. Could he escape? Would he be in time to prevent a crime of such proportions, of such disquieting possibilities?

He stiffened at a stealthy movement of the key in the lock. The answer lay just ahead. Garth could not doubt that the German was about to enter, to annihilate in his subtle manner an enemy he believed unarmed.

With his left hand he braced himself against the door-frame for the stroke, while with his right hand he lifted the knife. The necessity of striking without warning sickened him. He had no choice. There was too much eager help within ear-shot of an alarm. The stakes loomed too commandingly to tolerate a sentimental hesitation. It was not only his own life in the scales. The lives of those who toiled at the furnaces swayed with his. But it was from the recollection of Nora that he drew the most strength, from the desire to see her again; to watch her quiet figure—a little inscrutable, unconsciously provocative; to hover again on the edge of an avowal, alert for his favorable moment.

The door hinges responded to a pressure. The lamp had evidently been extinguished again, for he saw in the uncertain radiance of the embers a thing, scarcely definable as human, prone beyond the threshold.

The empty doorway, the inert object on the floor, the darkness, accented rather than diminished by the embers, blurred his calculations. Where was the one who had opened and for whom his knife was eager?

Unexpectedly a brilliant light flashed in his eyes and went out. Half-blinded, he sensed the presence of something on the sill, and he struck downward with all his force. He reached only emptiness. The one on the sill had sprung through. From somewhere in the house Garth heard the patter of hastening feet.

He fought away the effects of the flash, striving to locate the one who had entered. There beside the heap of rubbish knelt a form darker than the white darkness.

He moved noiselessly over. He reached down and grasped the bent shoulder, and, as the shoulder recoiled from his touch, so he recoiled from its quality that revealed the presence in his prison of a woman.

Through his amazement he heard the door close, but he felt sure of himself now. Mrs. Alden was his prisoner—a hostage, if he chose, for his own escape, unless, indeed, she had finally revolted and come to his aid.

"Get up," he said roughly.

The woman's sigh conveyed relief. Something scraped beneath her hand. A tiny flame was born and entered into the base of the rubbish.

Then the woman turned slowly, and, in the light of the flame, Garth looked into Nora's excited eyes and smiling face.

Incredulous, he grasped her arms, lifted her to her feet, and stared. The growing flame struck a flash from his knife, drove into his brain a full realization of the monstrous misunderstanding which had nearly involved them in unspeakable disaster.

"Good God, Nora! I nearly—I tried to—"

Her smile grew.

"I didn't know what I should find in here. I couldn't afford to take chances."

"But I left you in New York," he went on uncertainly. "How did you come? Why are you here?"

"No time for explanations now," she answered quickly. "We must get out of here."

He recalled the patter of hastening feet, the soft closing of the door. In the growing light he saw its tin-sheeted face flush with the wall.

"The door has been shut," he said. "I'm afraid—locked. Why did you light that fire?"

She ran across, grasped the knob, then commenced to beat with her fists at the tin. Suddenly she stopped. Her shoulders drooped.

"No use," she whispered. "She must have come in. She won't open now."

Garth hurried to her side.

"I don't understand," he said, "but it's evident we are caught here, and that fire has been fixed—a signal?"

She nodded.

"Why did you light it?"

"Because," she answered dully, "it had to burn to-night."

The crisis they faced was clear to him.

"Nora! In a minute this room will be a furnace."

He imagined from the excitement still flashing in her eyes that she did not quite realize, but she spoke without regret, and her words carried the shocking fatality of the German's.

"I'm sorry, Jim, but if I had known we would be caught I would have lighted it just the same. After all, a small price in the long run—only the two of us."

He brushed the rapid perspiration from his face. The fire had reached the heart of the pile. The air thickened with a reddish, pungent smoke. He choked.

"I'm sorry, Jim. I came only to help you, but I found—"

The vapour cut her voice.

The sentimental possibilities of their predicament came with a gentle wonder to Garth. They over-weighed the danger, robbed him for the moment of full comprehension. This clearly was his moment, and whatever the next might bring seemed a fair exchange for her probable response. He reached blindly towards her through the smoke.

"Nora!"

His heart leapt as she swayed a little. Then he heard the grating of the key in the lock. It impressed him as curious that the saving sound carried to him a sense of disappointment, the emptiness of a destiny unfulfilled.

Nora turned the knob. He pushed against the door. They stumbled into the next room, breathing deeply the fresh, clean air.

Alden's prostrate form lay just within. His wife stood across the room by the hall door, the revolver held listlessly in her hand. Her hair, more than ever disordered, fell about her weary eyes, and gave her face an air of ironical witchery.

Garth caught the meaning of the tableau. He glanced with admiration at the sick man, appreciating the bitter obstacle he had overcome, the abhorrent chance he had taken after conquering his physical incapacity and reaching the door. The result, Garth noticed, had carried to Alden a vast relief, a shadow of content. The light from the conservatory flickered about his face, exposing an expression of pride. The silent lips moved as if to frame a boast.

"So, Mrs. Alden," Garth said, "you left him again. To warn the others?"

She did not answer. He shrugged his shoulders.

"Anyway," he went on, "when you came back and found him at the key you didn't have time to get to him, and you weren't quite as bad as you should have been. You let him unlock the door. You didn't have the nerve to shoot—your husband."

"Don't, Jim," Nora warned. "You don't understand."

Frankly he didn't, but he knew that Mrs. Alden, in a sense, still controlled the situation. Her revolver could compel their movements. Its explosion would doubtless bring help swarming to her side.

"And you see," Nora went on, speaking to her gently, "what a useless sacrifice it would have been. Everything was finished for you the moment I lighted the beacon."

Mrs. Alden nodded.

Garth grinned as the protective feminine instinct expressed itself through this woman in her most intricate hour.

"It was all arranged," she said. "If you will close that door the house will be safe enough from the fire."

She indicated her husband. There were tears in her eyes again.

"You will take care of him?"

"Yes," Nora said.

She turned and closed the door. Through the sudden darkness Garth heard Mrs. Alden run into the hall. He sprang after her, but Nora's voice, sharp and commanding, halted him.

"Let her go, Jim. I'll explain. Light the lamp now."

"You've earned the right to give the orders," he said.

He felt his way to the writing-table and lighted the lamp.

"You know," he said, "that there are many men near here—that they can trap us in this house?"

"I don't think," she answered, "that they will come to this house again."

He turned to her.

"Nora! What is it? Even after all I've seen I can't be sure. The furnaces? They are two miles away."

She shook her head.

"Not the furnaces, Jim. Come with me and I will show you."

She led him to an unlighted room across the hall and flung back the curtains.

The glare of a conflagration, far vaster than that which had threatened them in the conservatory, flashed in their eyes and lighted the neighborhood with a brilliancy fiercer than noonday.

For the first time Garth could see that the house stood on a high, wooded plateau. The trees had been cleared away between it and the water, and a slope, bordered with hedges, had been blasted to a beach, small and crescent-shaped. The fire blazed with a destructive violence in a structure on this beach. He recalled the driver's gossip about Alden's yacht. He saw a small launch, heavily-laden, making for the open sea.

"The boat house," he said.

"Yes," Nora answered. "Look."

She drew a little back. An explosion tore at their ears. Somewheres upstairs a window broke. The tinkling of glass was like an absurdly attenuated echo. But Garth's attention was fixed on the boat-house. The building appeared to disintegrate. Out of its ruins rose a colossal column of muddy smoke. From its summit streaming banners of purple and violet flame unfurled. They waved their frantic message to Garth. He turned, gaping, to Nora.

"That building!" he gasped. "It's crowded with gasolene—oil!"

"You didn't guess, Jim? You see now I couldn't take chances. I had to light the signal that made them fire this."

"And you were right," he agreed. "Only the two of us—"

He gazed at her wonderingly. There was only pride in his voice.

"How many lives! How many millions of dollars! You've spared them, Nora."

Garth had lifted Alden to the sofa and had left Nora hovering over the man who, they knew now, had been systematically drugged for days. After reconnecting the telephone and notifying the federal authorities he had returned to the living-room. Nora arose, and, with her finger at her lips, joined him by the fireplace.

"He's asleep," she said. "You know, Jim, there wasn't much point in your telephoning. They've destroyed the evidence. They've gone."

She sat down. Garth drew a chair close to her. Their voices were low in order that Alden might not be disturbed.

"Was it near?" he asked. "The fact that they took the launch—yet they might put in at some lonely cove and scatter."

"It must have been expected soon," she answered. "They were working desperately. They were very anxious to-night."

"You must have guessed, Nora, as soon as I left New York. How?"

"By giving father a scolding," she answered with a smile. "I knew that Mrs. Alden had been born in Berlin, and that her family was still prominent there where Mr. Alden had married her. Even since her marriage she's spent much time abroad. I wondered what these shadowy figures were doing in the woods on foggy nights unless they were transporting something or working about some building. But Mr. Alden would know if it had anything to do with the house or the stable. Since he was sick, the boat-house might be their objective without his knowing it. I suspected the truth then. Such an opportunity! No one would doubt the property of a man who manufactured ammunition for the government. The natural thought was that any attempts by Germans here would be directed against the furnaces or Alden personally. It was ideal. All that was necessary was to scare the servants away and keep Alden in the house while his wife and the rest made ready for it."

"Still those men in the woods?" Garth asked.

"They were probably working at the furnaces. When you saw them they were on their way to the boat-house to make the necessary alterations. And, of course, they carried all the supplies there. You see, I went to the freight agent of the only railroad that runs to Deacon's Bay. He helped me a lot. We found that a large number of heavy cases had been sent here and to nearby stations, falsely invoiced and labelled to be called for. He had suspected gasolene in one of them and was about to hold up further shipments. That settled it for me. I knew you were going blindly, so I took the next train."

"How did you learn about the signal?" he asked.

"I came very quietly," she answered, "a little like a sneak-thief, I'm afraid. That front window is a little open. I overheard Mrs. Alden and a huge man. Of course she was only to light that signal if the game was wholly up. It meant to them that there was a party big enough to handle the lot of them. So I made up my mind I must slip in and burn it to-night, in case it was near by. I knew then they would burn the evidence, escape themselves, while the submarine would turn back, believing that the game was up."

"What a base!" he muttered. "With the trans-atlantic lanes at its mercy. All those transports and freighters marked for destruction! Alden saved the fat."

"Yes," Nora answered, "I gathered from what they said that he made sure to-night somehow and faced her with it. That was when she screamed and tried to send you out. Then her courage failed her and she called you back. She wasn't strong enough for murder. And from her point of view what she did was pure patriotism."

"It was because he suspected his wife, poor devil," Garth answered, "that he'd tell me nothing. I guess he hoped I'd convince him he was wrong."

He had been staring at the fire. He looked up now to find that Nora was knitting complacently on something heavy and comfortable and grey. Her eyes were thoughtful.

"Wife against husband," she mused. "Such tragedies are common in war. And she loved him. Have you noticed the conservatory door?"

It stood open. Through the glass Garth could see the far sea, still ruddy from the fire, and there entered again into his consciousness the restless clamor of water.

"He made me open it," Nora went on. "He looked out there until he went to sleep—a sort of farewell, a welcome if she should come back. Perhaps she will some day."

Such devotion stirred anew in Garth the sensations he had experienced in the conservatory. He watched Nora as her fingers moved with their accustomed deftness about her knitting. She made the old picture, lovable and tempting, of quiet, house-wifely efficiency.

"You always knit," he said in an uncertain voice.

"Another winter is very close," she answered gravely, "and if the peace should be delayed there would be so much suffering—"

He stretched out his hand.

"Nora," he said huskily, "you've saved my life to-night. It's yours. What will you do with it?"

She glanced up. She smiled a little.

"You very nearly took mine, Jim, so aren't we quits?"