Watson lived in a modest frame house set well back in its grounds and shaded by some fine old trees. Burton was thankful to find that he had, after all, come with reasonable directness to the place. There was no light in the windows to show that any one was up, but he went to the front door and tapped softly in a preconcerted fashion. The door was opened at once by Watson himself, who drew him into the hall, and then guided him through the darkness into an inner room. Here he removed the hood from a small lamp, and revealed the fact that there was another man in the room. It proved to be Ralston. He looked at Burton with a quizzical smile.

"Watson thought it would be best to let me in on this," he said, in a low voice. "He knew that I would never have forgiven him if he hadn\'t."

"That\'s all right. I\'m glad you are here," said Burton. He guessed that Watson, at the last moment, had needed some confirmation of this irregular project, and he was glad that he had been inspired to appeal to Ralston rather than to any one else. Ralston had imagination, and therefore was better equipped for seeing a truth that is not yet revealed.

"I was afraid I might be late," he added. And then he told of his explorations in unknown territory and of the outcry he had heard from the house on Larch Street.

Watson listened with professional attention. "Did it sound like a cry for help?" he asked.

"It sounded like the cry of some one in terror. It might have been some one in a nightmare. There was no other sound and no disturbance."

"You don\'t know the house?"

"No. It was a two-story frame house, narrow and high, with a porch in front. It was on the west side of Larch, and the next cross-street this way from it is James. I noticed that as I came along."

"Why, that\'s Selby\'s house!" exclaimed Ralston. "The plot thickens. I don\'t know why Selby shouldn\'t have a nightmare if he wants to, as well as any other man, but it looks rather significant that he should have a nightmare on this particular night, doesn\'t it, now?"

Watson was looking at Burton with a puzzled air.

"If anything has happened to Selby, we might as well know it," said Burton, answering his look.

"I\'ll telephone to the station," said Watson, and stepped out of the room.

"What made you say to Selby, instead of of, by, for, or from Selby?" asked Ralston curiously. "What makes you think anything could have happened to Selby?"

"I hope nothing has," said Burton abruptly, "--but--"

"But what?"

"Don\'t tell Watson yet. He\'ll feel that he ought to investigate, and I want to keep him still for an hour or two. But the truth is, I\'m uncomfortable over that cry, now that I come to think of it, because Henry Underwood is loose somewhere in town tonight."

"I thought Watson said he was under special guard."

"He was. He got away--through the window. I was passing the house and was just in time to see him escaping, but could not stop him. Of course it doesn\'t necessarily follow--"

"No, of course it doesn\'t," said Ralston, though he looked serious. "Henry wasn\'t in love with Selby, but it doesn\'t follow that he would--use violence in any way."

"Of course not," echoed Burton. In his own mind he was pushing away the thought of Selby\'s newly announced engagement as though he would force himself to ignore its significance. It was like the final bit in a puzzle which so obviously solves the whole mystery that no argument about its fitness is needed.

Watson returned softly. "I\'ve sent a man out to look Selby\'s place over," he said quietly. "He won\'t let himself be seen unless he is satisfied something is wrong. Now, if you please, I\'ll take you upstairs. You\'ll have to follow me without a light."

He guided them to a rear room on the second floor with an open window looking out into the darkness of the night.

"The woodshed roof is just below this window," said Watson, "and there\'s a ladder against the shed. If any one really wanted to break into this house, he would have an easy job of it tonight."

"Houses burgled while you wait," laughed Ralston, excitedly.

"It looks all right," said Burton. "Now, if anything is to happen, we\'d better keep quiet."

They settled into convenient chairs to wait.

To set a trap is one thing. To catch the quarry is quite another. It does not always follow the setting of the trap, even when there are tracks enough on the ground to warrant some confidence. Burton realized keenly that there were a thousand chances for his failure to one for success. And yet something that was more like the intuition of the hunter than plain reason kept him quietly hopeful through the draggingly slow minutes. He had set the day as the limit of their vigil, and though he could not read the face of his watch he knew that they must have been sitting quiet for something like an hour when there was the sudden tinkle of the telephone bell downstairs.

"Don\'t answer it," he murmured, as Watson rose softly.

"I must," Watson answered, in the same undertone. "No one outside can either see or hear me. It may be something important."

He went softly down the stairs and they heard him close the door of the room below before he answered the call.

"I\'ll bet you something has happened to Selby," said Ralston, a quiver of excitement in his guarded voice. "Take me up? Come, now, before Watson gets back! I\'ll make it two to one! In anything you like. Three to one! Five to one!"

"Cut that out," said Burton impatiently. "Keep still." He fancied he had heard a sound outside, and every nerve was strained to make sure of it.

But at that moment the door below opened abruptly, and Watson came up the stairs in a hurry.

"You may as well drop this tomfoolery," he said, at the door, speaking without precaution or care. "Selby is dead,--stabbed through the heart. My men have found Henry Underwood\'s cuff-button beside the bed, and they\'ll soon have him. That\'s what comes of your theatrical plans, Mr. Burton, and of my cursed foolishness in letting Henry out of jail. This is a pretty night\'s work."

"Oh, why didn\'t you take me up?" exclaimed Ralston, in a rapture of excitement.

"Hush!" said Burton suddenly. He thought again that he heard that faint sound outside. Unconsciously he caught each of the other men by the arm, and drew them back against the wall.

Was it a shadow that darkened against the sky,--a shadow in the shape of a man that swung up over the window-ledge in light swift silence, and was poised for an instant against the patch of light that marked the place of the window? Something had dropped into the room as softly as a cat. There was a moment of absolute stillness. Burton held his breath and tried to hush the noisy beating of his heart. Then there came the soft scratch of a safety match, and a point of light marked a spot in the darkness. Then a candle wick caught the point and nursed it into a light, and a man\'s face was revealed.

Watson\'s muscles had been tense under Burton\'s detaining hand. Now he whistled shrilly and at the same instant leaped forward and closed with the intruder. There was a moment\'s struggle, and then the room was suddenly lit as two men who had been stationed outside rushed in with lights. The chief was down on the floor with the man he had assailed. For a moment they all fought in a furious mêlée, but the policemen met brute strength with brute strength, and the click of the handcuffs told the end. Then they lifted the man to his feet, and Watson held the lamp close to his sullen face. After a long look he turned to Burton.

"You were right," he said, and set the lamp upon the table. His hand was not quite steady.

"You don\'t mean it!" exclaimed Ralston, staring hard at the unknown face of the man. "Is it possible that it really is--Ben Bussey?"

"No one else," said Watson, stooping to pick up a bundle that had fallen on the floor. It was a loosely tied package of rags, soaked in kerosene.

"That\'s the way the Sprigg house was fired," he said.

Ben parted his lips, but it was not to speak. His teeth were locked tight behind his snarling lips. His eyes were set on Burton.

"How long have you been doing this sort of thing?" persisted Ralston, studying Ben with a curiosity that could not be satisfied. "Those old tricks that we all laid up against Henry,--did you do that, too?"

Ben turned his head at that and looked at his questioner. The look of triumph that flashed into his eyes was as plain as any words could have been, but he did not answer otherwise.

"Take him to the station," Watson said to his men.

But Burton interposed. He had been watching Ben, and he saw that if they were to get anything from him in the way of an admission, he must be goaded into speech before he had time to fully realize the advantages of standing persistently mute.

"No hurry about that," he said, with a slight sign to the chief. "I want to tell you something about how I got on this trail, and Ben may as well hear it."

"There are important matters waiting," Watson reminded him, in a significant aside.

"Nothing more important than this--now," said Burton. Watson hesitated, but drew back, leaving Ben, with a policeman on either side of him, where the light fell on his somber face.

"I was first positively convinced that Henry Underwood was not the man on the night of the Hadley assault," Burton began, with deliberation. "That knotting of the rope was too neat for a man with a forefinger as stiff as a wooden peg. You made a mistake that time, Ben. Didn\'t your mother tell you that Henry had cut his finger?"

But Ben refused to be drawn. He lifted his upper lip over his closed teeth, but gave no other sign of attending.

"Of course it was clear from the first that the person who was making the trouble had easy access to the Underwood house and very up-to-date information about everything that went on in the house. At first I, too, thought it must be Henry. Then, when I satisfied myself that it wasn\'t, I began to keep a watch on Selby."

"Poor old Selby," said Ralston, with sudden recollection.

"Poor old Henry," said Burton sternly. "He has been goaded past endurance. Selby\'s slate was by no means clear, though I acquit him of many of my suspicions. But I am telling you now why I suspected him. He hated Henry and was jealous of him. He was a party to the discovery of Henry\'s knife near the Sprigg house, and I thought I had reason to believe he had himself dropped it there. He had access to the Red House through his business relations with Ben, and Mrs. Bussey was an eavesdropper and spy who could easily have given him the inside information required. Finally he had in his possession a number of Indian baskets and was known to have been much among the Indians as a boy. I was certain that the strong and supple fingers that had twisted the lilac bushes into a net to hold the Sprigg baby and that had knotted the cords into a snare about Mr. Hadley had learned the trick of Indian weaving when they were young."

Ben\'s chest heaved. He was looking at Burton with a look that made Watson glance warningly at the officers who stood beside him. Burton went on with his nerve-trying deliberation.

"I went up to the Reservation with the hope of finding some one who would remember teaching young Selby how to tie the peculiar and unusual knot I had noticed. I found Ehimmeshunka, who makes the baskets, and the old chief Washitonka, who knew Ben\'s father, but I could not get them to talk about the old times. How did you get word to them to hold their tongue, Ben?"

Ben affected not to hear. Watson looked up in quick surprise as though he would have spoken, and then checked himself. The others, who understood by this time Burton\'s plan of exasperating Ben into speech, said nothing.

"Finally, just as I was leaving, Pahrunta, who sells the baskets to travellers at the station, gave me a clue. By the way," he added, turning to Ralston, "there was a bit of poetic justice in that. The first day I was in High Ridge, I saw Selby rudely strike away her arm, when she tried to stop him to speak to him. It was in revenge for that blow that she gave me the information I wanted and which I could not get from the others. She showed me an old daguerreotype with Selby\'s portrait in it. It must have been an old keepsake given by him in the early days when they were friends. There was another portrait in it also,--Ben\'s. Then it occurred to me that Ben was more likely to have learned basket making than Selby, because he had an aptitude for handicrafts. He had all the opportunities Selby had,--provided he could walk. In order to find out whether his paralysis was a sham, I arranged with Watson to have an alarm of fire given at such a time that I should have an opportunity of observing Ben immediately before and immediately after. I spilled a red powder over his clothing just as ............