Grace Duvall, on being left at the hotel by her husband, spent a long and very tiresome afternoon. She had expected Richard back long before, with news, perhaps, of a successful investigation of the woman, Marcia Ford, whose address was so near that of the Mortons. But when six o'clock came, and went, with no news of her husband, Grace came to the conclusion that he had probably struck a long trail, and being a normally healthy person, with an excellent appetite, she went to the dining room and ordered dinner, leaving word at the desk where she would be, in case Richard returned.

Her lonely meal was over by seven, and, not knowing what to do next, Grace went out on the sidewalk, with the intention of looking for her friend of the evening before, the taxicab driver, Leary. It was possible that the man might have something more to report. As she reached the door, she saw him descend from his cab. He came forward at once, tipping his cap.

"Taxi, ma'am," he asked.

"No, I don't think so, Leary. Anything new?"

"Not a thing, ma'am. Haven't seen that party since. Can't I take you for a drive, ma'am?"

Grace was on the point of refusing, when a sudden idea came to her. She hastily opened her pocketbook, tore out the pieces of the visiting card that Duvall had left upon the table, and fitted them together.

"Drive me to 162 W. 57th Street," she directed, and stepped into the cab.

Leary touched his cap, and in a few moments they were speeding up the Avenue.

"Don't go right up to the address," Grace told him through the speaking tube. "Stop a little below, but in a place where I can see the door."

The man nodded, and a little later they turned into 57th Street and drew up alongside the curb.

"Do you think you would recognize the woman who gave you the card, last night?" Grace asked.

"Yes, ma'am. I think I should, ma'am."

"Very well. Watch the doorway of number 162. If she goes in let me know. If she comes out, follow her. I shall probably recognize her myself, if she is the woman I think. I saw her for a few moments at the Grand Theater last night. But she may not be the same one. We'll know that later."

Leary nodded, and they began a long wait. After what seemed to Grace an interminable time, they saw a taxicab come rapidly down the street, execute a turn, and draw up before the door of number 162.

Grace, as soon as she realized the cab's destination, sprang to the sidewalk and strolled carelessly along in the direction of the house. The cab came to a standstill just before she reached it, and two women got out. One of them Grace had never seen before. The other she recognized at once. It was the woman who had fainted in the theater the previous night.

Neither of the women paid any attention to her, but directing the cabman to wait, passed quickly into the house.

Grace went back to her cab and got in.

"The woman I am looking for has just driven up in that cab," she said. "She has gone into the house. The cab is to wait. When she comes out again, follow her." Leary nodded, and the two of them settled down for what they supposed would be a long wait. To their surprise, scarcely ten minutes had passed before the door of No. 162 was suddenly opened, and the woman whom Grace had recognized dashed down the steps and sprang into the waiting cab. At almost the same moment Grace saw her husband start forward from the direction of the apartment building, as though in pursuit of her.

There was no time, however, to wait for him. The cab ahead had already started off, and Leary, true to his instructions, was speeding after it. In a moment both vehicles had turned into Seventh Avenue and were driving rapidly uptown.

As minute after minute sped by, Grace began to realize that the chase might prove a long one. They had already crossed to Central Park West, and were now speeding northward again in the neighborhood of 72nd Street. Then, to Grace's surprise, the cab ahead swerved into a side street, and drew up before the entrance of the hotel at which Ruth Morton and her mother were stopping. The cab had no sooner stopped than the woman sprang out and entered the lobby.

Grace followed her without a moment's hesitation, ordering Leary to wait. The woman hurried up to the desk and, taking a blank card from it, scribbled a few words upon it in pencil, and handed it to the clerk. Grace was unable to hear what she said to him, but the man nodded, and handed the card to a bellboy. The woman sat down in a nearby chair.

Grace, having nothing else to do, and being somewhat afraid that the woman might recognize her, crossed at once to the opposite side of the lobby and, going to the news stand, spent some time in selecting and purchasing a magazine. She stood with her back to the woman, screened by a large palm, but at the same time managed to keep a fairly close watch upon her.

It was several minutes before anything happened. Then an elderly lady emerged from one of the elevators, and under the guidance of a bellboy approached the woman Grace had been following. Grace did not remember having ever seen the older woman before, but she had a distinct impression that it might be Mrs. Morton. She strolled over to the desk, and addressed the clerk in a low voice.

"Is that Mrs. Morton—the elderly lady in black?" she asked. The clerk stared at her, but his reserve melted before her charming smile.

"No, Miss," he said. "That is Mrs. Bradley."

"Thank you." Grace gave a sigh of relief, and turned away.

Looking once more toward the two women, she saw that the older one was addressing her companion with something of reserve, as though she had never met her before. The younger woman spoke quickly, smilingly, for a few moments, shook hands with her companion, and turned away. Grace saw that she was about to leave, and at once followed her, although at a little distance, so as not to excite her suspicions. When she reached the sidewalk the other woman had already entered her cab, and seemed about to drive off.

The cab, however, merely moved to a position a little further down the street, and by the time Grace had entered her own vehicle the other had again become stationary.

This maneuver struck Grace as extremely peculiar. She told Leary to remain where he was, and with some misgivings, awaited the woman's next move.

After a time she saw Mrs. Bradley, who had gone toward the elevators as Grace left the lobby, come out, signal for a taxicab, and drive quickly off. Leary was obliged to draw up with his machine, in order to leave a clear space before the door.

A few seconds later Grace saw the woman she had been following spring from her cab, come rapidly along the sidewalk, and once more enter the lobby. Grace again followed her, just in time to see that instead of applying at the desk, as before, she went directly to one of the elevators, entered, and was whisked out of sight.

Grace's heart almost stood still with fear. She had not appreciated the meaning of the woman's actions before. Now they were only too clear. She had evidently gotten Mrs. Morton, whom Grace suddenly remembered had been registered under an assumed name, out of the way on some pretext or other, and had gone to Ruth's room, with the intention, no doubt, of carrying out her previous threats. The situation was frightful. It would admit of no delay. Grace dashed to the desk and began to speak rapidly, in a frightened voice, to the clerk.

"That woman"—she exclaimed—"the one who just went up in the elevator—she is going to Miss Ruth Morton's room—you must stop her—there is no telling what she may not do—send up, quick—quick! Miss Morton is in the greatest danger."

The clerk looked at her, his mouth half open with surprise.

"I—what do you mean, Miss? I don't understand you. We have no Miss Morton here." He regarded Grace apprehensively, and out of the corner of his eye looked toward the cashier, as though he contemplated calling on him for assistance in case this apparently mad woman became violent.

Grace gave a groan of despair.

"The daughter of the elderly lady, about whom I asked you before. Her name is Morton. Her daughter Ruth is staying here under an assumed name—Bradley, you say it is. Oh—please be quick. I know what I am talking about. That woman who came here a while ago is a dangerous character. She gave Mrs. Morton some message or other to get her out of the way, and as soon as she had gone came back into the hotel and went upstairs in the elevator. Didn't you see her?"

"Yes, Miss, I saw her. She was a friend of Mrs. Bradley's, she said, and I supposed Mrs. Bradley had told her to go upstairs."

"I tell you, that woman who just went upstairs means harm—terrible harm, to Miss Bradley—Miss Morton. Oh—don't stand there wasting time. Come up with me at once, and you will see that I am right——"

"But—who are you, Miss? What have you to do with the matter?"

"What difference does that make, if what I say is true? If you must know, I am a detective employed by Mrs. Morton——"

"Employed by Mrs. Morton! And yet you didn't know her when you saw her! My dear woman, your story does not hang together——"

"It is my husband, Mr. Duvall, who is employed by her. He was registered here under the name of Bradley, too. I am trying to help him."

"Oh!" The clerk seemed somewhat more inclined to accord her serious attention. "Very well. I will go to the room with you, and see if everything is all right."

"And hurry, please—hurry." Grace started toward the elevators.

Then a sudden thought came to her. Suppose the woman was to make her escape, coming down in one of the elevators, while she and the clerk were going up in another. There had been ample time, she knew, for her to have murdered Ruth, were that her plan, and have already left the room.

"Wait just a moment," she cried to the clerk, who had said a few words to one of his assistants and was leaving the desk to join her. "I must speak to my cabman, but I'll be back in a moment." She dashed through the entrance doors and hurried to the point where Leary sat at his steering wheel.

"Wait here," she whispered to him, "until I come back, unless the woman we have been following comes out. If she does come out, and drive away, follow her, and find out where she goes. Then telephone me here. I will leave my name at the desk, and wait until I hear from you."

Leary nodded, and Grace quickly re-entered the lobby and joined the waiting clerk.

"Instruct your telephone operators," she said to him, "to let me know, in case anyone calls up Mrs. Duvall."

The clerk gave the necessary instructions, and the two then entered one of the elevators and quickly made their way to the seventh floor, upon which Mrs. Morton's apartment was located.

There was no one in the corridor when they left the elevator, and the clerk, who knew the location of the suite, hastened to it at once.

They reached the door. Grace was conscious of a feeling of apprehension, a sense of impending disaster. Her heart pounded violently as she waited for the answer to the clerk's knocks. She waited in vain. Only silence, grim, terrible, rewarded his efforts.

"Something has happened," Grace whispered, as the clerk again rapped upon the door, this time more loudly than before.

Again there was no reply, no evidence of the presence of anyone in the girl's rooms.

"Open the door!" Grace cried. "Something terrible must have occurred!"

The clerk took the pass key with which he had provided himself, and inserted it in the lock. A moment later the door swung open, and the two of them entered the room.

It was in total darkness. Grace clutched at her heart, fearing what she believed the switching on of the lights would reveal. The clerk, without loss of time, pressed the push button near the door. The room was at once flooded with light.

Grace glanced about, then gave a momentary sigh of relief. The room, the small parlor of the suite, was quite vacant. At its further end the door to Ruth Morton's bedroom stood ajar.

With the clerk beside her, Grace hurriedly crossed the room. With a prayer in her heart she pushed open the bedroom door. Her companion at the same moment felt along the door-jamb for the electric switch. In an instant the bedroom lights were turned on.

Then Grace saw that her fears had been fully justified. On the floor, halfway between the door and the bed, lay Ruth Morton, apparently lifeless. Her face was the color of chalk, her eyes were closed. With a cry, Grace fell on her knees beside the unconscious girl and with trembling fingers felt her heart. The clerk, a weak-faced young man, stood gazing at the scene before him in amazed horror.

"She isn't dead!" Grace exclaimed, turning an excited face to him. "Her heart is still beating. Send for a doctor, quick!" Then, taking the unconscious girl in her arms, she lifted her to the bed.