Room 15 was a plain, comfortable office in a plain, comfortable building on Clay Street, not far from the heart of the business district. It was on the second floor, and its one window opened to the rear, and faced a desolate assortment of back yards, rear walls, and rickety stairways. The floor had a worn carpet, and there was a desk, a few chairs and a shelf of law books. The place looked as though it had belonged to a lawyer in reduced circumstances, and I could but wonder how it had come into the possession of Doddridge Knapp, and what had become of its former occupant.

I tried to thrust aside a spirit of melancholy, and looked narrowly to the opportunities offered by the room for attack and defense. The walls were solidly built. The window-casement showed an unusual depth for a building of that height. The wall had been put in to withstand an earthquake shock. The door opening into the hall, the door into Room 16, and the window furnished the three avenues of possible attack or retreat. The window upon examination appeared impracticable. There was a sheer drop of twenty feet, without a projection of any kind below it. The ledge was hardly an inch wide. The iron shutters by which it might be closed did not swing within ten feet of any other window. The one chance of getting in by this line was to drop a rope ladder from the roof. The door opening into Room 16 was not heavy, and the lock was a cheap affair. A good kick would send the whole thing into splinters. As it swung into Number 16 and not into my room it could not be braced with a barricade. Plainly it was not a good place to spend the night should Doddridge Knapp care to engineer another case of mysterious disappearance.

The depression of spirits that progressed with my survey of the room deepened into gloom as I flung myself into the arm-chair before the desk, and tried to plan some way out of the tangle in which I was involved. How was I, single-handed, to contend against the power of the richest man in the city, and bring home to him the murder of Henry Wilton? I could look for no assistance from the police. The words of Detective Coogan were enough to show that only the most convincing proof of guilt, backed by fear of public sentiment, could bring the department to raise a finger against him. And how could I hope to rouse that public sentiment? What would my word count against that of the King of the Street?

Where was the motive for the crime? Until that was made clear I could not hope to piece together the scraps of evidence into a solid structure of proof. And what motive could there be that would reconcile the Doddridge Knapp who sought the life of Henry Wilton, with the Doddridge Knapp of this morning, who was ready to engage him in his confidential business? And had I the right to accept any part in his business? It had the flavor of treachery about it; yet it seemed the only possible chance to come upon the secret springs of his acts, to come in touch with the tools and accomplices in his crime. And the unknown mission, that had brought Henry to his death? How was I to play his part in that? And even if I could take his place, how was I to serve the mysterious employer and Doddridge Knapp at the same time, when Doddridge Knapp was ready to murder me to gain the Unknown's secret.

Fatigue and loss of sleep deepened the dejection of mind that oppressed me with these insistent questions, and as I vainly struggled against it, carried me at last into the oblivion of dreamless slumber.

The next I knew I was awaking to the sound of breaking glass. It was dark but for a feeble light that came from the window. Every bone in my body ached from the cramped position in which I had slept, and it seemed an age before I could rouse myself to act. It was, however, but a second before I was on my feet, revolver in hand, with the desk between me and a possible assailant.

Silence, threatening, oppressive, surrounded me as I stood listening, watching, for the next move. Then I heard a low chuckle, as of some one struggling to restrain his laughter; and so far from sympathizing with his mirth, I was tempted to try the effect of a shot as an assistance in suppressing it.

“I thought the transom was open,” said a low voice, which still seemed to be struggling with suppressed laughter.

“I guess it woke him up,” said another and harsher voice. “I heard a noise in there.”

“You're certain he's there?” asked the first voice with another chuckle.

“Sure, Dicky. I saw him go in, and Porter and I have taken turns on watch ever since.”

“Well, it's time he came out,” said Dicky. “He can't be asleep after that racket. Say!” he called, “Harry! What's the matter with you? If you're dead let us know.”

They appeared friendly, but I hesitated in framing an answer.

“We'll have to break down the door, I guess,” said Dicky. “Something must have happened.” And a resounding kick shook the panel.

“Hold on!” I cried. “What's wanted?”

“Oh,” said Dicky sarcastically. “You've come to life again, have you.”

“Well, I'm not dead yet.”

“Then strike a light and let us in. And take a look at that reminder you'll find wrapped around the rock I heaved through the transom. I thought it was open.” And Dicky went off into another series of chuckles in appreciation of his mistake.

“All right,” I said. I was not entirely trustful, and after I had lighted the gas-jet I picked up the stone that lay among the fragments of glass, and unwrapped the paper. The sheet bore only the words:

This was the name of the agent of the Unknown, who had sent the other note. Dicky and his companion must then be protectors instead of enemies. I hastened to unlock the door, and in walked my two visitors.

The first was a young man, tall, well-made, with a shrewd, good-humored countenance, and a ready, confident air about him. I had no trouble in picking him out as the amused Dicky. The other was a black-bearded giant, who followed stolidly in the wake of the younger man.

“You've led me a pretty chase,” said Dicky. “If it hadn't been for Pork Chops here, I shouldn't have found you till the cows come home.”

“Well, what's up now?” I asked.

“Why, you ought to know,” said Dicky with evident surprise. “But you'd better be hurrying down to Borton's. The gang must be there by now.”

I could only wonder who Borton might be, and where his place was, and what connection he might have with the mystery, as Dicky took me by the arm and hurried me out into the darkness. The chill night air served to nerve instead of depress my spirits, as the garrulous Dicky unconsciously guided me to the meeting-place, joyously narrating some amusing adventure of the day, while the heavy retainer stalked in silence behind.

Down near the foot of Jackson Street, where the smell of bilge-water and the wash of the sewers grew stronger, and the masts of vessels could just be seen in the darkness outlined against the sky, Dicky suddenly stopped and drew me into a doorway. Our retainer disappeared at the same instant, and the street was apparently deserted. Then out of the night the shape of a man approached with silent steps.

“Five-sixteen,” croaked Dicky.

The man gave a visible start.

“Sixteen-five,” he croaked in return.

“Any signs?” whispered Dicky.

“Six men went up stairs across the street. Every one of them did the sailor-drunk act.”

“Sure they weren't sailors?”

“Well, when six coves goes up the same stairs trying the same dodge, all inside of ten minutes, I has a right to my suspicions. And Darby Meeker ain't been to sea yet that I knows on.”

“Darby Meeker!” exclaimed Dicky in a whisper. And he drew a whistle under his breath. “What do you think of that, Wilton? I had no idea he was back from that wild-goose chase you sent him on.”

“It looks bad,” I admitted cautiously. “I dare say he isn't in good temper.”

“You'll have to settle with him for that piece of business,” said Dicky with a chuckle.

I failed to see the amusing side of the prospect. I wished I knew what Mr. Meeker looked like.

The guard had melted away into the darkness without another word, and we hurried forward with due caution. Just past the next corner was a lighted room, and the sound of voices broke the quiet. A triangular glass lantern projected from above the door, and such of the paint as had not weathered away made the announcement:

{Illustration: BORTON'S Meals Liquors Lodgings}

We pushed open the door and walked in. The room was large and dingy, the ceiling low. Tables were scattered about the sanded floor. A bar took up the side of the room next the entrance, and a general air of disreputability filled the place. The only attempts at ornament, unless the arrangement of various-colored bottles behind the bar came under that head, were the circles and festoons of dirty cut paper hanging from the ceiling.

About the room, some at the tables, some at the bar, were numbers of stout, rough-looking men, with a few Greek fishermen and two or three sailors.

Behind the bar sat a woman whose appearance in that place almost startled me. She might have been nearing seventy, and a hard and evil life had left its marks on her bent frame and her gaunt face. Her leathery cheeks were lined deep, and a hawk-like nose emphasized the unpleasant suggestions conveyed by her face and figure. But the most remarkable feature about her was her eyes. There was no trace of age in them. Bright and keen as the eyes of a rat, they gave me an unpleasant thrill as I felt her gaze fixed upon me when I entered the door, arm in arm with Dicky. It was as though they had pierced me through, and had laid bare something I would have concealed. It was a relief to pass beyond her into a recessed part of the room where her gaze might waste itself on the back of my head.

“Mother Borton's up late to-night,” said Dicky thoughtfully, as he ordered wine.

“You can't blame her for thinking that this crowd needs watching,” I suggested with as much of airiness as I could throw into my manner.

Dicky shook his head for a second, and then resumed his light-hearted, bantering way. Yet I could see that he was perplexed and anxious about something that had come to his attention on our arrival.

“You'll not want to attend to business till all the boys are here?” asked Dicky.

“Not unless there's something to be done,” I responded dryly.

Dicky gave me a quick glance.

“Of course,” he said with a laugh that was not quite easy, “not unless there's something to be done. But I thought there was something.”

“You've got a fine mind for thinking, Dicky,” I replied. “You'd better cultivate it.”

“Well, they say there's nothing like society for that sort of cultivation,” said Dicky with another laugh. “They don't say what kind, but I've got a pretty good stock here to choose from.” He was at his ease in banter again, but it struck unpleasantly on me that there was something behind.

“Oh, here's a queer friend,” he said suddenly, looking to the door. “I'd better speak to him on the matter of countersigns.”

“By all means,” I said, turning in my chair to survey the new-comer.

I saw the face for an instant. The man wore a sou'wester, and he had drawn his thick, rough coat up as though he would hide his head under the collar. Cheek and chin I could see were covered by a thick blond beard. His movements were apparently clumsy, but his figure was lithe and sinuous. And his eyes! Once seen they never could be forgotten. At their glance, beard and sou'wester dropped away before my fancy, and I saw in my inner vision the man of the serpent glance who had chilled my spirit when I had first put foot in the city. It flashed on me in an instant that this was the same man disguised, who had ventured into the midst of his enemies to see what he might learn of their plans.

As I watched Dicky advance and greet the new-comer with apparent inquiry, a low harsh voice behind gave me a start of surprise.

“This is your wine, I think,”—and a lean, wrinkled arm passed over my shoulder, and a wrinkled face came near my own.

I turned quickly. It was Mother Borton, leering at me with no apparent interest but in her errand.

“What are you doing here?” asked the crone in a voice still lower. “You're not the one they take you to be, but you're none the less in danger. What are you doing with his looks, and in this place? Look out for that man you're with, and the other. Yes, sir,” her voice rose. “A small bottle of the white; in a minute, sir.”

I understood her as Dicky and the new-comer came to the table and took seats opposite. I commanded my face to give no sign of suspicion, but the warning put me on the alert. I had come on the supposition that I was to meet the band to which Henry Wilton belonged. Instead of being among friends, however, it seemed now that I was among enemies.

“It's all right,” said Dicky carelessly. “He's been sent.”

“That's lucky,” said I with equal unconcern. “We may need an extra hand before morning.”

The new-comer could not repress a triumphant flash in the serpent eyes.

“I'm the one for your job,” he said hoarsely, his face as impassive as a stone wall.

“What do you know about the job?” I asked suspiciously.

“Only what I've been told,” he answered.

“And that is—”

“That it's a job for silence, secrecy, and—”

“Spondulicks,” said Dicky with a laugh, as the other hesitated for a word.

“Just so,” said the man.

“And what else?” I continued, pressing him firmly.

“Well,” he admitted hoarsely, “I learned as how there was to be a change of place to-night, and I might be needed.”

I looked at him inquiringly. Perhaps I was on the threshold of knowledge of this cursed business from the mouth of the enemy.

“I heard as how the boy was to be put in a safer place,” he said, wagging his head with affected gravity.

Some imp put it into my brain to try him with an unexpected bit of news.

“Oh,” I said coolly, “that's all attended to. The change was made yesterday.”

The effect of this announcement was extraordinary. The man started with an oath.

“The hell you say!” he exclaimed in a low, smooth voice, far different from the harsh tone he had used thus far. Then he leaped to his feet, with uncontrollable rage.

“Tricked—by God!” he shouted impulsively, and smote the table with his fist.

His outburst threw the room into confusion. Men sprang from their chairs. Glasses and bottles fell with clinking crash. Oaths and shouts arose from the crowd.

“Damn you, I'll have it out of you!” said the man with suppressed fury, his voice once again smooth and low. “Where is the boy?”

He smote the table again; and with that stroke the false beard fell from his chin and cheek, and exposed the malignant face, distorted with rage. A feeling of horrible repulsion came over me, and I should have struck at that serpent's head but for a startling occurrence. As he spoke, a wild scream rose upon the air, and as it echoed through the room the lights went out.

The scream was repeated, and after an instant's silence there rose a chorus of shouts and oaths, mingled with the crash of tables and the clink of breaking glass and crockery, as the men in the room fought their way to the door.

“Oh, my God, I'm cut!” came in a shriek out of the darkness and clamor; and there followed the flash of a pistol and a report that boomed like a cannon in that confined place.

My eyes had not been idle after the warning of Mother Borton, and in an instant I had decided what to do. I had figured out what I conceived to be the plan of the house, and thought I knew a way of escape. There were two doors at the rear of the room, and facing me. One led, as I knew, to the kitchen; the other opened, I reasoned, on a stair to the lodging-rooms above.

Before the scream that accompanied the extinction of the lights had died away, I had made a dive beneath the table, and, lifting with all my might, had sent it crashing over with my enemy under it. With one leap I cleared the remaining table that lay between me and the door. And with the clamor behind me, I turned the knob and bounded up the stairs, three steps at a time.