As Bat Scanlon saw Nora disappear around the Burton house he once more awaited some developments from the shadows; but again there was no sign of the presence of either the Swiss or the lank burglar. So after a little he moved on until he reached the gate of the adjoining house and quietly lifted the latch.

A dog, from somewhere in the darkness, barked; Bat halted and listened, but there were no further sounds, and so he went on. Placing his hands upon the low division fence he bounded over upon the Burton lawn. Almost directly before him was the rose arbor behind which Ashton-Kirk had discovered the woman's footprints; and the big athlete took his place in the deep shadow of this and looked about. The window of the Burton sitting-room was lighted; inside was Mary Burton in her reclining chair, propped up by pillows, and reading. The shaded lamp cast a soft glow upon her; the white face wore an expression of suffering, and with this was a meekness, a submission which made it nun-like.

A woman's form flitted between Scanlon and the window; it stopped, and then the watcher saw Nora Cavanaugh peering in at the sick girl.

"Her notions of a social call seem to have picked up a twist somewhere," said Bat, to himself. "What's the idea?"

However, Nora only remained at the window for a few moments; then she disappeared in the direction from which she had come. In Bat's mind was a picture of two lurking men, the lank desperado, and the mild looking, yet murderous, Swiss; and he felt a chill of fear as he gazed into the darkness which had swallowed the girl up. A moment or two passed, then he heard the quick br-r-r-r! of an electric bell from the house.

"The door-bell," said Bat. "Through the sound of a hundred others I'd match myself to pick the one attached to the door of any house. They are all of the same family."

Another little pause; then he saw Nora in the sitting-room, the nurse behind her, and the sick girl reaching out her hand gladly. Bat breathed a sigh of relief.

"All right," said he. "Inside, she's not so likely to meet those gentlemen."

The nurse disappeared from the sitting-room; Nora sat down and began to talk with the invalid, earnestly. Outside all was still; after a little, Bat searched the surrounding shadows intently for anything that might indicate the whereabouts of Big Slim and Bohlmier; but the darkness was silent and complete. The windows of the houses opposite and adjoining were lighted; from one some little distance away came the faint tinkling of a mandolin, and the deeper sounding strings of a guitar; from still another came fresh young voices singing an evening hymn. Figures could be seen through the windows or silhouetted upon the shades; at one Bat saw a tiny girl and a very large dog who seemed her especial chum; they romped gaily; Bat heard the child laugh and the dog bark.

"Nice," he mused. "Nice and homey. Regular Sunday night stuff in the bosom of the family. But no sign of the two gentlemen who did the shadowing. They are lying low, I guess, same as I am."

He gave his attention once more to the sitting-room; Nora and the sick girl were still engaged in conversation. As Bat looked, Nora took a crumpled newspaper page from her hand-bag, as though it were a part of what she was telling. The girl in the chair lifted herself up, eagerly, took the paper in her hand and read the staring head-lines. Then Bat saw it flutter to the floor, he saw her sit upright for a moment, gazing at Nora with wide-opened eyes; she sank back suddenly and heavily upon the cushions.

"Fainted!" said Bat, excitedly, leaning forward. He saw Nora arise quickly and bend over the girl, then he saw her open the door. "Calling the nurse," said he.

In a moment the nurse was in the room; and under the care of the two the invalid was soon restored to consciousness. Then followed a period of comforting, of patting pillows into shape, of cheerful assurance. Nora then kissed the invalid and bid her good-bye. She left the room with the nurse following her.

"Just came, evidently, to give her the news," said Bat to himself. "But I wonder why the haste. It wasn't the kind of news that would give joy or anything like that."

In a few moments he heard the front door close, and steps upon the walk. These ceased after a moment; there was silence; and then, to his amazement, Nora once more flitted through the darkness and came between himself and the window.

"There is a reason for it," said Bat. "She's not doing all this out of just idle curiosity. But what it leads to is a thing I don't——"

The thought was halted, unfinished, in his mind; for through the darkness, quite close at hand, came a cautiously moving shape; and from its direction, it was also seeking the shelter of the rose arbor. There was a door in the far side of the latter, as Bat had noticed on the day of Ashton-Kirk's investigation; he slipped quietly around and in at this; and through the trellis work he watched what was proceeding outside. The first glance showed him that Nora was now, also, moving toward the arbor, and the thought of what might occur upon her meeting with the prowler in the dark caused Scanlon's hand to go inquiringly to the big revolver which he carried in the breast pocket of his coat, and to shift it to a place where it would be more convenient.

But, though he strained his eyes to catch some indications of the shadowy figure he had seen only a moment or two before, he could not do so; it had vanished. This did not add anything to the big athlete's quietude of mind; for the footsteps of Nora, dulled by springy sod, were now close at hand.

The girl reached the arbor and took up the position which Bat had lately occupied; and he knew that she had settled herself for a vigil—to watch all that passed in the sitting-room of the Burton house. Naturally, the eyes of the big man also went in that direction once more.

The nurse had returned to the room and was bending over the invalid, a glass in her hand. The girl lay motionless, her face turned upward and her thin hands pathetically folded. The nurse, after she had succeeded in inducing the patient to take a few drops of what she held to her lips, busied herself with some things upon a small table near the chair; then she left the room.

There was a pause; no movement came from the room whatsoever. Bat fancied that the sick girl had gone to sleep; but this thought had no sooner taken shape in his mind than he saw her stir. Then she arose slowly in the chair, and sat, apparently listening, her manner surprisingly alert. Only a few moments ago she had shown every sign of exhaustion; now her strength was unquestioned, for her body was firmly held and her grip upon the arms of the chair was sure.

There came a little gasp from Nora crouching behind the rose arbor.

"Surprised!" thought Bat. "And no wonder! I'm just a little bit that way myself."

Mary Burton threw back the blanket in which she was swathed, and stood up. She wore a long dressing gown, tied about the waist; from a pocket of this she took something, and then after a moment of listening approached an old mahogany high-boy, unlocked and opened a drawer and looked into it. Almost at once it was slid back into place and relocked; the girl stood poised for an instant, as though not sure as to what her next movement would be; then she went tiptoeing to the door, opened it, and disappeared.

Nora drew a long breath; and Scanlon, as he stood, amazed, felt like echoing it. But the next instant all that which had happened in the sitting-room, surprising as it had been, was wiped from his mind. From outside there came a low-pitched voice, that of old Bohlmier:

"Do not make some noise!" it said. A gasp came from Nora, a gasp which would have been a scream if fear had not suppressed it. "I will talk a little with you, if you blease."

There was an instant's silence; Bat pressed hard against the trellis work of the arbor—only a few inches separated him from the girl outside, and he could hear her breath catching sharply in her throat as she spoke.

"Who are you?"

"We will nod speak of that," said the Swiss. "Only we will talk of things that interesting are."

This seemed to have a tonic effect upon Nora; when she answered her breathing had become almost normal; her voice was strong and held some confidence.

"I know you now," she said. "I saw you the other night."

Old Bohlmier chuckled.

"Ach! yes, the other night. You saw me, yes, but you spoke to me not! Now it will the other way be. Eh?"

"What do you want?" asked Nora, sharply.

"Do you so ask?" Bohlmier's tone was one of astonishment. "Is it possible? There is one supject only which we can talk about Is it not so? One supject. Yes?"

"I thought I told your friend all I had to say about that," said the girl.

"Ach! no! It is not true." If he had been able to see the old rascal, Scanlon was sure his head would be wagging and a mild smile would be upon his face. "You told him so—yes. But it is not true. Much more have you to say. Blenty more. And you will say it to me, eh? Now!"

The vision Bat had in his mind became more and more clear; not only would the bald head be moving from side to side, but it would be thrust forward in the deadly snake-like motion which the big athlete had seen once before. And the smile? He had never seen one like that which his ear told him Bohlmier's would be—a mild, quizzical smile which was a habit of the muscles only, and through which a pair of eyes gleamed with devilish purpose.

"Has he got me nervous, or something?" Bat asked himself. "Or do I call the turn on him right?"

"My friend," proceeded the old Swiss, "is a chentleman much ezberienced in certain things. In others he has not so much exberience as that," and the listener heard him snap his fingers, sharply. "Not so much as that! And so he let you go without some understandings."

Bat heard Nora laugh. It was not a pleasant laugh; nevertheless it caused a thrill of pleasure to shoot through him.

"Good!" he thought. "She has her nerve with her. He hasn't scared her even a little bit."

"Perhaps," said Nora, to Bohlmier, "you have the experience he lacked?"

"I haf the handling of many affairs had," came the voice of the Swiss, smoothly. "And from the first I asked for this one; for I knew, dear lady, I could the resulds get."

"You mean you thought you could frighten me where he failed." Again Nora laughed. "You have confidence." Then with a note of curiosity in her voice: "What would you have done?"

A sudden sharp movement came from outside the rose arbor; Bat heard the hissing of Bohlmier's breath and a sharp cry from Nora. A diminished light ray, unseen in any other way, was caught upon the uplifted blade of a knife; then Bat drove his arms through the frail trellis work; with the left hand he gripped the arm of the Swiss and twisted it wickedly. The knife was heard to strike against the side of the arbor as it fell. Bat's right hand, at the same instant, slipped along the man's body and gripped his throat like iron; and as he held him, he heard the muffled sound of Nora's steps as she fled away.