When the crowded police van had left, Nora, Garth, and the inspector stepped into the crisp night air.

"Garth," the inspector said, "you and Nora ought to have medals or something. That pale-face at the head of the gang is Jerry Smith. He must have been sent on from San Francisco. If there's a country-wide syndicate of crime he's on the board of directors along with your old friend Slim."

"Some day," Garth said, "that syndicate will be tapped properly."

Nora, after her experience in the heavy, repellent atmosphere of the house, was anxious to remain in the air. She proposed that they walk down town.

Garth, aware of her displeasure, scarcely dared suggest an answer to his curiosity, but the inspector, in a happier mood, did not hesitate.

"Maybe, Nora, you'll tell us how you got in that dive as a first class housemaid."

"There was only one way I could think of," she answered. "The place was bound to make cases for Bellevue, so I went to the head nurse and took her into my confidence. She kept me posted. At every chance I went there and was apparently ill myself of the same dreadful illness as the patient in the next cot. About two weeks ago the head nurse telephoned me a case had come in which looked promising. I've been there since. I'll confess, the best I hoped for was the number of the house, but this girl grew confidential finally. She had actually worked there. When she found she couldn't go back for a long time, and learned that I was about to be discharged as cured, she whispered a telephone number and a name. She said they would want somebody and it was hard to get just the right kind. I called up last night and told them about her and my anxiety for the place. A meeting was arranged with Smith in a cafÉ. He wouldn't give me the address, but he agreed to take me there this afternoon. You see he wouldn't have let me out again until he was sure of me—no afternoons off there."

"Clever, Nora," the inspector muttered.

She shook her head.

"Only choosing the best chance. I knew I couldn't trace them in any obvious fashion. They were too careful. Few customers had the run of the place. The stuff was taken to the rest. The way they had Black followed last night to make sure he left no trail shows how they accounted for everything. He had evidently been seen answering to that generous symptom of his before."

Garth noticed that she did not speak to him directly, but her resentment could not completely veil her relief at his safety, her appreciation of the courage that had urged him to her rescue, her gratitude that his daring had brought about the end she had so ardently desired. He hoped, moreover, that there was, about her quiet manner, something to be followed to that necessary but impulsive moment in the brown radiance of the evil house.

Yet that illusion she did not permit him to hold for long. He left the inspector and her at the flat with an uncomfortable feeling of having failed to measure up to the idea of him she had developed. She did not mention Black again, but her restraint persisted. Sooner or later, he tried to tell himself, something would destroy that—probably another case that would throw them together, that would make them depend one upon the other.

At headquarters one day the doorman told him that the inspector had been taken ill. The detective satisfied himself that nothing serious was to be feared, so he smiled, thinking the situation might offer something useful for himself.

It was really the trivial fact of the inspector's cold that involved Nora and Garth in the troubles of Addington Alsop. Those gathered into one of the most daring and dangerous cases headquarters had had since the commencement of the period of reconstruction.

To begin with, the inspector's indisposition confined him to his flat. It held Nora there in the part of a nurse. It drew Garth, who would have braved the most virulent contagion to be near her. Most important of all, it allowed the mighty Alsop to apply for police help without fear of detection by the reporters and agents constantly swarming at headquarters.

When Garth entered the flat that afternoon, he was, unknowingly, already on the threshold of the strange case; for he had read in the noon editions the brief paragraph which recited an accident to all appearances common enough. A man had been picked up unconscious in the middle of a quiet street. Evidently he had been struck by an automobile. Two details, however, arrested Garth's attention. The victim, Ralph Brown, he knew as a successful private detective. Moreover, the outrage had occurred during the slack hours before the dawn. Apparently no clue as to its perpetrators remained. Garth spoke of that casually to the inspector. The huge, suffering man was scarcely intrigued. Wrapped in an ancient dressing-gown, his throat smothered beneath flannel, he sat in an easy chair, facing the fire, whose coals he perpetually reproved with a frown. He groaned. There was utter despair in the rumbling, animal-like note. Nora laughed.

"Laugh away," the inspector roared, "but make Garth forget he's a detective if he can't do better than hound a sick man with a cheap automobile case."

From her dark and striking face Nora's quiet eyes smiled sympathetically at Garth.

"These unimportant things, father, are sometimes the most important of all," she said. "Jim's right. It's odd no witnesses can be found."

As if there had been something prophetic in her words and her attitude, a muffled knock came from the outer door.

"Why doesn't he ring?" the inspector growled. "You haven't had the bell disconnected, Nora? Good Lord! Am I as sick as that?"

Nora, a trifle bewildered, moved towards the door. "Queer! And I think there are two in the hall."

Garth, as he always did, marveled at her acute perception. For, although he had heard no footsteps, no voices, two men followed Nora into the living room. The one in advance was young, with a frightened and apprehensive face. His companion was older and portlier, with narrow eyes and full-blooded cheeks. And those eyes were uneasy. For Garth they did not quite veil a sense of sheer terror. With a growing discomfort he guessed the cause of this visit.

Nora's voice betrayed none of the amazement Garth knew she felt.

"It's Mr. Alsop, father," she said—"Mr. Addington Alsop."

The inspector had already struggled to rise. He conceded the importance of this unexpected call. He apologized for his failure.

"Nora's got me wound up like a mummy—"

Alsop broke in rapidly.

"No politeness, inspector. I must speak to you. I'm up against it. They're after me."

He sat down heavily. The young man, whom he introduced as his secretary, Arthur Marvin, lighted a cigarette with trembling fingers. Garth watched them both while the inspector explained that they might speak freely before him and Nora. Alsop, he knew, because of his genius for organizing money and industry, and his utter ruthlessness in dealing with those whom necessity had thrown within his power, had made dangerous and active enemies. Garth was aware, moreover, that recently Alsop had publicly defied certain organizations which had asked what he believed to be too much. The detective could understand the financier's position. His death might be a cheap risk for outside fanatics to take to destroy his leadership against the forces of radicalism, for there were few men strong enough to replace him. Alsop had a newspaper in his hand now, and was holding it out to the inspector, while with his forefinger he tapped the paragraph which told of Brown's accident.

"No accident," he muttered. "That man worked for me—a precaution any fool would take. Well, he must have found out what he was after last night, and they got him, and thought they had killed him. They tell me at the hospital he's still unconscious."

Nora smiled at her father.

"A cheap automobile case!" she reminded him softly.

Alsop handed Garth a crumpled, torn, and soiled post-card.

"That came in the noon mail. Must have been picked up by somebody and dropped in a post box. I figure Brown, before they got him, threw it out of a window, or some such thing. Anyway that settled it. It brought me here for a quiet talk."

Garth read the card. A single line, almost undecipherable, sprawled across the back:

"Danger to-morrow night. Brown."

"That means to-night," Garth said. "Had you planned anything important for to-night?"

Marvin laughed a little. Alsop spread his hands.

"The conference with capitalists and politicians at which we settle on certain legislation that will put some of these foreign anarchists on the skids, snatch American labor beyond their influence, and give the honest business man a chance to make a fair profit by driving his men as he should. See here, inspector. I'm not afraid of good Americans. They may put me out of business, but if they do, I'll know I've been beaten in a fair fight. It's these damned foreign anarchists and some sore central Europeans I'm afraid of. I expect some important men from Wall Street and Washington to-night. I can't let them walk into a bomb, and I don't want any high explosives myself."

The inspector grunted.

"Nasty situation. I'm no politician. Fight crime. We'll see what we can do. It's a good thing you found Garth here."

Garth, who had not ceased to study Alsop's face, realized that the man had more to report—something which he shrank, however, from mentioning.

"What is it, Mr. Alsop?" he asked. "You've something else to tell us."

Nora, who had clearly noticed the same symptoms, nodded approvingly. Alsop flushed and glanced at Marvin. The secretary knocked the ashes from his cigarette. The trembling of his fingers was more apparent.

"You should tell that by all means, Mr. Alsop," he said in a low voice. "That's what I want to find out. If I don't get some explanation of that I'll doubt my sanity."

Alsop cleared his throat.

"A ghost story," he said with an attempt at a laugh. "Fact is, Marvin and I and some of the servants are haunted by a veiled woman."

Nora came closer. The inspector turned back to the fire a little contemptuously. But Garth had no doubt that this hard-headed business man was serious.

"Go on," he said softly. "You think this ghost is connected with a dangerous conspiracy against you?"

"I can only tell you facts and let you judge," Alsop answered. "I daresay you know about my house on the river near the city line. It is lonely for that neighbourhood, and very old. I've always heard stories about a ghost, a veiled woman on the upper floor—some connection with the suicide of a beautiful girl long ago. You know the sort of thing. It's always told about old houses. The point is, I saw that veiled woman last night, and she gave me rather too much evidence of spirituality."

"Why do you connect a ghost with anarchists?" the inspector demanded.

"Because," Alsop answered, perfectly seriously, "I believe the thing was after my papers."

Garth laughed outright.

"Then why suspect your visitor of being a ghost?"

"Because," Alsop said patiently, "this visitor had every appearance of walking through a locked door."

Nora alone was thoroughly impressed.

"Tell us," she urged.

"I've a safe in my room," Alsop said, "and as an extra precaution, when I've had important papers at the house, I've locked my door. I went upstairs late last night. There was no light in the upper hall, but a glow came from the lamps downstairs. In this sort of radiance I saw the figure of a woman, clothed in white, her face hidden behind a white veil, come apparently from my room, cross the hall, and disappear. I cried out. I sprang for the door. It was locked. Marvin and I searched the house. My daughters are in Florida. The only women in the place were servants. There seemed no way in or out of the house without the collusion of one of these. And I've had them a long time. It's hard to suspect them. Besides, Marvin has had much the same experience. Tell them, Arthur."

"As a motive," Marvin said slowly, "I might mention the fact that I often take my work upstairs—letters of Mr. Alsop's to answer, statements to make out. The first time the thing happened was Thursday night. It must have been after midnight. I was in bed. I awakened with that uncomfortable feeling of being no longer alone. At first I saw nothing. The only light in the room came from a dying moon. I had been nervous for several nights, fearing an attempt on Mr. Alsop. I never could get him to take that very seriously until to-day. At any rate, after a long time, I saw this figure that Mr. Alsop describes. It did not seem to come from anywhere."

He commenced to pace up and down the room. There was about the sudden gesture of his hand a despairing belief that shocked Garth.

"The thing—white veil and all—seemed to materialize out of nothing. It moved softly about the room as if searching—searching. I thought of the letters on my desk. I called out instinctively, 'Who's there?' There was no reply. The figure did not hurry. It stepped behind a screen by the fireplace. I sprang up and went there. I couldn't believe the evidence of my eyes. There was no one—nothing behind the screen. I examined the door. It was locked as I had left it, with the key on the inside. There was no way in or out of that room. Yet the veiled woman had been there, and had gone, leaving no trace."

"The windows," Garth said, "or the fireplace?"

Marvin shook his head.

"The windows were scarcely open, and a fire burned in the fireplace. And, mind you, this was before Mr. Alsop had seen the woman. I mean, he had not suggested the vision to me. The same thing happened last night. That figure came searching and disappeared in the same impossible way. I knew I wasn't dreaming then. I spoke of it to Mr. Alsop. It frightens me. I want an explanation of that."

"Catch your enemies and you'll catch your ghost," Garth said drily. "I'd like a shot at both."

"What you want," the inspector said to Alsop and Marvin, "is protection for yourselves and your distinguished guests. What the police want is to catch these fellows red-handed. We'll try to fit the two things. Don't lose your nerve. Go ahead with your conference, and trust Garth to find out how your veiled woman gets in and out of the house and through locked doors. I should say if we find her we should have the brains of the conspiracy. There may be no danger for you to-night. We've only Brown's post card to go on. That looks serious, and I'll do my best to protect you. But you must give me every chance to nab these birds. This sort of thing's getting too bold. There's too much foreign propaganda in this country. It would please me to throw the fear of Uncle Sam into such people."

And when Nora had gone to the door with Alsop and Marvin, he called Garth over, and hurriedly whispered:

"It's a big chance, Garth, but dangerous as dynamite. These fellows won't hesitate to blow that house up if they can't block Alsop's dirty politics any other way. And remember, you're fighting a woman who behaves like a ghost. Take it from me, she's the one you've got to be afraid of. She has the brains."

"If I could get something out of Brown," Garth mused.

"Maybe he's conscious now," the inspector said. "Run up to the hospital, then look over the neighborhood where he was found. Come back here by five, and we'll lay our plans."

Nora stopped Garth in the hall.

"Jim," she breathed, "you're going to take this case?"

"Surely. I've only to lay a ghost. That ought to be simple."

She hesitated.

"I've been thinking," she said, "and I wish you wouldn't go, because it will be hard, terribly hard—with death always in the way."