Leaving all cabs at home this time, they proceeded in couples by different streets to a rendezvous at the northeast corner of Stuyvesant Square. Greg and Estuban walked up First Avenue to Seventeenth, then west to the meeting-place, thus passing the house that was their objective.

Their examination of it revealed these salient facts: there was no light in any window; the basement windows were protected by iron bars, the basement door by an iron gate, while above, before the front door, heavy oak storm-doors were closed. In short, a wholly unpromising prospect.

"We need an ax to get into this," said Estuban dejectedly.

"We'll have to try the rear," said Greg.

The question then was how to get around to the back. The whole block presented an unbroken brick front from First Avenue to the Square.

At the Square they joined the other men and Pa Simmons who was there with his cab. The latter reported that de Socotra had not left the house.

"Damn glad you come," said he. "I'm at the end of my wits, how to keep watching that house without the police force getting wise to me cab. I watches from this corner for awhile, then runs around the block and takes a stand down by First. Then I come back again. But there's a cop down there's got his eye on me already. I don' know where to go now."

"You can be our mobile scout," said Greg. "Keep moving. Drive through this block every minute. We'll signal you if we need you."

Pa Simmons drove off.

At the corner where they stood there was a modern apartment house. A space of three feet separated the back wall of this building from the side wall of the first dwelling. This crack offered the only discoverable opening into the interior of the block. As the house they were seeking to enter was the sixth from the corner, it meant that they must climb six back fences to reach it.

"Bull, how are you on climbing fences?" asked Greg.

"O.K., if somebody will hold me overcoat."

"Hand it to one of the fellows. Estuban, Bull and I will go over the fences and break in the back way. You other fellows hide yourselves up and down the block here, but choose places where you can watch that house. If anybody comes out you are to jump on him and frisk him for the little black book, see? If it isn't on him let him go. If we get in the rear all right, and want your help, one of us will come to the front door, and saw his arm up and down so, like a semaphore."

There was a flight of steps down to the rear basement-door of the apartment house. An eight-foot fence separated the narrow yard here from the yard of the first dwelling. Greg and Estuban boosted Bull up on top; Bull from the top and Greg at the bottom hoisted Estuban up; then the two already up each reached Greg a hand. Once up they found the way was easier than they had expected. There was a longitudinal fence separating the yards of all the houses on Seventeenth Street from those in Sixteenth. This fence was topped by a three-inch plank along which Greg and Estuban were able to walk upright. Bull, less sure-footed, straddled it and hunched himself along. At one of the back yards a cautious householder had set his fence with great spikes against cats or marauders. Here they had to drop down and go around. The sky was overcast and it was very dark. Few lights showed in the back windows.

They reached the sixth yard at last and silently dropped to earth. The back of the house facing them at first glance showed no gleam of light, but upon looking closer they saw that the principal room on the second floor was lighted. In two of the three windows on this floor cracks of light showed around the edges of the opaque blinds that had been pulled down. Two windows and a door gave on the yard. The windows were barred, so they could be left open in hot weather, but the door had no outer protection, and glass panes had been let in the upper panels.

"Here's where the glass-cutter comes in handy," murmured Greg. "Good old Bessie!"

They wrapped a handkerchief around the tool to deaden the sound as far as possible. Nearest to the lock of the door Greg traced a square big enough to admit his hand. There wras nothing to do but let the piece fall inside.

"If the sound of it brings them we'll already be in," said Greg grimly.

He struck the outlined square a light blow with his fist and it tinkled to the floor within. Thrusting his arm through the hole he drew the bolt and turned the key. They stole in. Greg gave his pocket light a swift flash around. They were in a kitchen, a disused kitchen; the range was gray with dust, the shelves empty.

"Wait here a minute till we see if they were alarmed by the sound," whispered Greg. "Keep on this side away from the windows."

They waited, holding their breaths to listen. Not a sound was to be heard through the dark house except the rats scurrying behind the plaster.

Satisfied at length that the broken glass had passed unnoticed, they proceeded to investigate their surroundings. Four doors faced them; two gave on cupboards, the third on a short passage ending in the front basement room, while the fourth opened on the stair hall. The other room on this floor was as empty as the kitchen. Though so far there was no sign of human usage they were struck by the warmth of the house.

"They don't stint themselves coal," whispered Greg. "Let's drop our overcoats."

A door under the stairs gave on steps leading to the cellar. A gaslight had been left burning down here. They saw the furnace that supplied the heat, but there was no person in the cellar.

Greg left Bull on guard on the basement floor. "If anybody gets past us up-stairs, don't let him get by you without frisking him for the book. If they come too fast for you, call for help."

Greg and Estuban stole up to the main floor. Two long parlors front and rear opened off the hall. They were dusty and empty like the rooms below. At the head of the next flight of stairs a crack of light showed under a door, and a murmur of voices came down to them.

Greg whispered to Estuban: "Creep up stairs and listen. It may be valuable to us. I'll call the other men in."

With infinite caution Greg unchained and unlocked the two sets of doors and stepped out on the stoop. The block was empty. But there were eyes out. For when Greg gave the prearranged signal three figures appeared from the shadows opposite and noiselessly hastened to him. He drew them inside the house and shut the doors.

Hickey was sent to help Bull because there were two ways out from the basement to be watched; Blossom was left at the front door; Greg and Ginger stole on up and joined Estuban at the turn of the stairs. Putting his lips to Greg's ear Estuban breathed:

"We're just in time. They're breaking up here. There are not more than four men with de Socotra in there. The rest have already scattered. He's giving these their final instructions now."

Greg whispered back: "Is the door locked?"

"I don't think so. There's no key in the other side. Now that you're here to back me up I'll try the handle."

"Wait a minute. Front and rear bedrooms in these houses usually communicate. Ginger, go in the front room and stand guard. Take my flash."

Estuban yielded first place to Greg. Greg tried the door. It gave. Slamming it open the two entered the room with their guns before them.

"Hands up, gentlemen," said Greg.

There were four men; three seated in various attitudes about a table near the window, and the fourth, de Socotra, arrested in the act of pacing back and forth. The table was littered with papers. Several valises stood about the floor. The three sitting men, Abanez and Alfieri were two of them, flung up their hands without a sound as if impelled by an electrical current. Not so de Socotra. His nerves were under iron control. He actually laughed. With his eyes fixed on Greg's eyes 'he coolly drew a cigarette case from his waistcoat pocket, took a cigarette, tapped it finically on the lid, and stuck it between his grinning lips. Returning the cigarette case, from another pocket he produced a match, struck it on his sole, lighted the cigarette and flicked the match away.

"Ah, our good friend Mr. Parr again," he said mockingly. "Really, Mr. Parr, you ought to be in moving pictures. Or perhaps you are. To what do I owe the pleasure of this call?"

If he expected to rattle Greg he mistook his man. Greg saw a tell-tale bulge over the man's right breast, and that was all he wanted. Matching the other's tone, he said:

"You're a remarkable man, Se?or de Socotra. I didn't want to lose touch with you. To-night I have brought an old acquaintance of yours with me."

De Socotra for the first looked at Estuban, and his eyes changed. The smile became a thought strained, but the voice was as cool as ever. "Ah, Estuban! How did you get out of jail?"

Estuban was incapable of this grim jesting. It was his first sight of the man responsible for the murder of his best friend, and his eyes burned. He answered de Socotra in Spanish. Whatever it was he said, it bit through the elder man's veneer of scorn. De Socotra snarled at him.

"Put up your hands," said Greg. "I shall not tell you again."

De Socotra obeyed. But his expression altered. He looked beyond and between Greg and Estuban and suddenly cried:

"Seize them both, Milio!"

In spite of themselves they looked behind them. Even as he turned, Greg was half sensible that it was a trick, but the subconscious impulse was irresistible. There was no one there, of course. They turned back. De Socotra was in the act of springing towards an open door in the corner. Like a flash Estuban's pistol sought him. Greg knocked his hand up, and the bullet went through the ceiling. De Socotra disappeared. The other three men, green with terror, never moved.

"Keep them covered," Greg shouted. "I'll get him."

He ran out through the hall and into the front room crying: "Hold him, Ginger!"

But he and Ginger only collided with each other in the empty room.

"He didn't come this way," gasped Ginger.

At the same moment back in the hall a door banged open. They ran out. An open closet door between the two rooms showed the way he had escaped. There was no sight nor sound of him. There were two other rooms on the floor, a bathroom presumably and a hall room, but he had not had time enough to get a door open and closed again, nor could he have gone down stairs for there was no sound from Blossom at the foot.

At the instant Greg made up his mind that he had gone up, a small bright beam of light flashed athwart the upper flight and threw a circle on the side wall. From above a voice said mockingly:

"Yes, I'm up here, Mr. Parr. Come on up. When you cross that light I'll give you something to bring with you."

The voice did not come from the spot whence the light issued. Evidently he had laid his light on the floor and retreated from it. For an instant Greg hesitated. Then it came to him what to do. Extending his body on the steps, pressing close to the rail where one on the upper landing could not see him, he snaked his way up a step at a time until he was within striking distance of the light. Taking careful aim, he fired. The light went out.

At the same moment he let his body relax and slid back down the stairs. But no answering shot came as he expected. Nor was there any sound of running feet above. De Socotra as usual was bluffing. While the light lay on the floor he had stolen away. Listening intently Greg heard some little sounds from the fourth and top story of the house. Snatching his light out of Ginger's hands he sprang up the stairs. Ginger followed at his heels.

In the h............