Duvall, on his arrival with Mrs. Morton at her apartment, lost no time in finding out from the clerk just what had happened. The story, pieced together, confirmed his worst suspicions.

The woman, after escaping from the house at 162 West 57th Street, had gone at once to Ruth\'s hotel, followed by Grace. Here she had interviewed Mrs. Morton, represented herself as Grace Duvall, and induced Mrs. Morton to leave the hotel by giving her a fictitious message purporting to be from himself.

Returning, later, to the hotel, she had gone to Ruth Morton\'s room and attacked her. The nature of that attack, the effect upon the girl, were as yet uncertain. Ruth Morton was still unconscious.

Meanwhile, as he learned from the clerk, Grace had received a telephone message and hurriedly left the hotel. The clerk did not know from whom the message had come.

Duvall went to Ruth Morton\'s bedroom, and called the doctor aside.

"What is the exact nature of Miss Morton\'s injuries?" he asked.

"She has no injuries, at least in the sense I think you mean. She is suffering solely from the effects of shock."

"What sort of shock?"

"I do not know, of course. Fright, of some sort, terrible fright, I should say. I am informed that some woman, some enemy of hers, came to this room, and was alone with her."

"There is no evidence of any violence?"

"None whatever. But the effects of shock are often worse than those of actual physical violence. They have frequently been known to cause death."

"You do not, I hope, anticipate anything of the sort in this case."

"I cannot say." The doctor shook his head. "She must have been very weak. Her system is responding very slowly."

Duvall glanced over to where Mrs. Morton hung in agonized silence over her daughter\'s bed, then went out into the sitting room. It seemed to him well nigh incredible that the woman responsible for all this had been able to move about, to elude pursuit, to carry out her threats, apparently without the least hesitation or fear of capture. His professional pride had received severe shock.

Two means of finding the woman, he felt, were still open to him. One was to trace her through Miss Ford. He did not doubt that, after what he had said to the latter, she would make an immediate attempt to warn her confederate of the danger that threatened her. Of course, the Ford girl might communicate with her companion by telephone, in which event the tracing would be difficult, if not impossible.

The other hope of tracing the woman lay in Grace. Why had she left the hotel so suddenly? He did not of course know the source of the telephone message, and could only surmise that Grace had in some way been able to pick up the woman\'s trail.

Leaving Mrs. Morton with a few words of encouragement, he made his way to his hotel. There was no news there of Grace, however, and he realized that it was now too late to accomplish anything by returning to the house on 57th Street. Marcia Ford would either have long since retired, or else would have left the house to communicate with the woman who had been with her earlier in the evening. Considerably upset by the events of the past three hours, Duvall retired to his room, and sat down to think the whole matter over.

Proceeding on the assumption that the woman in question, and Miss Ford were acting together, all the events at the studio, the fake telegram, the missing photograph, became intelligible. But the delivery of the letters in Ruth Morton\'s apartment, the strange attack upon him while searching the Ford girl\'s room, were by no means so clear. Once more his thoughts reverted to the attic room, the roof of the adjoining house, the problem of effecting an entrance to the Morton apartment through either of the two windows.

And then, as he revolved the problem in his mind, a sudden light came to him. He sprang from his chair with an exclamation of satisfaction. A solution of the whole matter flashed through his brain, a solution at once so simple, and so ingenious, that he wondered he had not thought of it before.

He glanced at his watch. It was midnight. Too late, perhaps, to test the accuracy of his deductions. Nor did he feel at all easy in his mind regarding Grace. Something must have happened to her, he feared, to keep her out so late, with no word to him concerning her movements. He went to the \'phone, and calling up the office, inquired whether anything had been heard of Mrs. Duvall.

"No," the night clerk informed him. Mrs. Duvall had not been heard from, nor had she sent any message. But a note had just been left for her. He would send it up.

Duvall awaited the arrival of the note with the utmost impatience. A message for Grace. From whom? What could it mean? A few moments later one of the bellboys thrust into his hand a letter, written on the note paper of the hotel.

He regarded the scrawling and ill-written superscription with apprehension, then tore open the envelope and proceeded to read the contents of the note.

"Dear Madam," it said. "I waited till nearly midnight. When you did not come, I thought you must have gone out some other way, so came back to the hotel. I hope I did right. Respectfully yours, Martin Leary." Duvall stared at the words before him with a look of alarm. Who was Martin Leary? And where had he waited for Grace until nearly midnight? And, above all, why had she not returned? Had some accident, some danger befallen her? The circumstances made it seem highly probable.

There was but one thing to do—to question the night clerk, and find out, if possible, who Leary was. He rushed to the elevator and made his way to the lobby with all speed.

"Who left this note for Mrs. Duvall?" he asked of the clerk.

"Why,"—the man paused for a moment—"one of the cabmen, I believe."

"Is his name Leary—Martin Leary?"

"Yes. It was Leary, come to think of it. Nothing wrong, I hope, Mr. Duvall."

"I\'ll know later. Where is Leary now?"

"Couldn\'t say, sir. You might ask the cab starter?"

Almost before the clerk had finished speaking, Duvall had darted across the lobby and made his way to the taxicab office at the door.

"Taxi, sir?" the man asked. "Do you know a chauffeur named Martin Leary?" exclaimed Duvall.

"Yes, sir. One of our regular men, sir."

"Where is he?"

The starter glanced along the row of taxicabs.

"He\'s turned in for the night, sir. Left for the garage some time ago. He\'s been on duty since early this morning."

"Where is the garage?"

"On Lexington Avenue, sir, near 30th Street."

"Does Leary sleep there?"

"No, sir. I don\'t think so, sir. They would know at the garage, I guess."

"Very well. Get me a cab. I want to be taken there at once."

The starter called to one of the drivers, and a few moments later Duvall was being driven at a rapid rate toward the garage.

His inquiries, on his arrival there, developed the fact that Leary had left for his home, on Second Avenue, some little time before. Duvall secured the address, and once more set out.

He felt greatly alarmed at Grace\'s failure to put in an appearance. Something must have happened to her. Clearly the case was going very much against him—the woman\'s second escape—the attack on Ruth Morton—now the disappearance of Grace. He felt that the time had come for action of a quick and drastic nature.

Leary lived with his wife and two children on the third floor of a Second Avenue tenement. Hastily climbing the two flights of dark steps, Duvall rapped on the door. He was overjoyed when it was opened by a man whom he judged to be the chauffeur himself.

"Are you Martin Leary?" he asked.

"Yes, sir." The man wiped his mouth with the back of his hand, choking down a bit of cold supper he had been eating, before turning in.

"I am Richard Duvall. You drove my wife uptown, somewhere, did you not?"

"Yes, sir. To Columbus Avenue and Ninety-sixth Street, sir. Won\'t you come in?"

"No. There isn\'t time. I want you to put on your coat and come along with me. Mrs. Duvall has not returned, and I am afraid something has happened to her."

The man turned and called to someone inside the flat.

"Gimme my hat and coat, Kitty," he said, then turned again to Duvall. "I suppose I should have waited, sir, but after two hours went by, I made up my mind that Mrs. Duvall didn\'t need me any longer."

"What is the building at Columbus Avenue and 96th Street?" Duvall asked, as the man, pulling on the coat his wife handed him, strode down the hall.

"An apartment building, sir."

"And why did Mrs. Duvall go there?"

"Well, sir, we was following a woman, sir. She went to a hotel on Seventy-second Street, and Mrs. Duvall told me to watch for her. I did, and tracked her to the place at 96th Street. Then I telephoned to Mrs. Duvall to come, and she did."

"What time was that?"

"About half-past nine, sir."

"All right. Go............