No volley greeted them.

There was no crash of vapor bombs, no cloud of pungent gas, no clash with desperate and determined criminals who fought on behalf of their leader and master!

There was nothing but silence—a silence broken only by the deep breathing of the sheriff and his deputies, who had sprawled into that hall expecting to meet with instant battle, and to whom the unexplained silence was more trying than combat.

Again Sheriff Kowen gave a signal, and one of the men opened the door at the end of the hall. They entered an ordinary living room that was adorned with cheap furniture; it might have been the living room of the home of a family in moderate circumstances.

They passed on to a small dining room, investigating an ordinary bedchamber. Sheriff Kowen began thinking that he had made a serious mistake.

"That woman came in here—and where is she now?" the sheriff said. "Search the rest of the house—go into the basement—don't leave a corner untouched. We're in here now, and we might as well do our work. That woman is here some place, remember that. We saw her come in, and she hasn't left."

They searched the kitchen, another small bedroom, and found nothing, neither a trace of Mamie Blanchard nor anything that would indicate that the cottage was a den of thieves. They located a trap door, and opened it, and saw a flight of steps running down into a dark basement.

"Careful!" Kowen warned his men. "They're probably down there waiting for us! We'll not all run into the trap!"

He delegated one man to remain above. He flashed his electric torch, but could see nothing except the flight of steps and the landing at the bottom. With some of the others close behind him, with his electric torch in one hand and his revolver in the other, Sheriff Kowen started to descend the steps.

Each instant they expected to hear the sound of a shot, or the explosion of a vapor bomb, or to encounter one of the traps rumor said the Black Star always had in his headquarters. Step by step they descended, but nothing happened.

They reached the landing, peered around the corner of a concrete projection. Sheriff Kowen gasped.

"Careful!" he warned again. "This is the headquarters, all right, and there doesn't seem to be anybody here—but you never can tell. Watch out for tricks and traps! Be careful what you touch and where you step. When he was after the Black Star before, Roger Verbeck found himself in a trap when he thought he was boss of the situation—don't forget that!"

The sheriff stepped to the floor, walked a couple of paces away from the steps. He saw an electric switch on the wall, hesitated a moment, and then turned it. The basement was bathed in light.

All the deputies with him were on the floor of the basement now. A chorus of gasps escaped them.

The basement was not like the rest of the house. It was furnished lavishly. In the middle was a long table. At either end was a blackboard on the wall. There were half a score of heavy chairs scattered about. There were some papers on the table.

"Watch the walls," Kowen instructed. "We've found the new headquarters, all right. We'll beat Roger Verbeck and the police this time, thank Heaven! Watch the walls—they're liable to open up and let a gang of thugs in on us any time. I'm going to look at these papers on the table."

He posted his deputies where he wished them, and advanced slowly and carefully across the floor. He was afraid the floor would open and swallow him, afraid of some clever trap that would turn victory into defeat and make him a laughingstock.

He reached the table without accident, and glanced at the papers there. There was no handwriting in sight. The papers had been printed with tiny rubber stamps. Kowen remembered that such was the Black Star's method.

He picked up the nearest and began reading. His eyes bulged and an exclamation escaped him.

"Great—great!" he muttered.

For he was holding in his hands some of the master rogue's orders to his band. Moreover, they had to do with the campaign of crime the Black Star had promised. Kowen read it swiftly:

Number Eleven reports that all is in readiness in his department. Number Four will be at his post a quarter of an hour before midnight. Number Ten will have charge of the men opening the vault. One of the watchmen is a man of ours and will attend to his companion; he is to be bound and gagged afterward by Number Eight, as we may need him again and do not want any suspicion attached to him. Automobiles will be at either end of the alley. Exit through basement door after work is done. The bags of gold are to be put in the limousine, which will be driven by Number Twenty.

"This is great!" Kowen told himself again. "If we only can nab the whole gang——"

He picked up another sheet of paper, and started reading that. Once more an exclamation of satisfaction escaped him.

Midnight, Tuesday. National Trust Company. Preliminary work completed. All who have received orders will act accordingly. Must be no failure in this first case. Loot will be heavy.

"Going to tap the National Trust, is he?" Sheriff Kowen said. "Well, we'll be ready for him at midnight! He's going to run into a bunch of trouble."

The chief deputy stepped to his side. "Suppose they find out that we have located their headquarters," he said.

"Let us hope they won't find it out," replied the sheriff. "Don't touch another thing here."

"How about that woman?"

"That's the one thing that puzzles me," the sheriff admitted. "She came in here, and we didn't see her leave, and I don't see where she can be. I suppose she came to get orders, or something like that."

"You can bet that there's some other way to get out of here," the deputy told him. "You can bet that the Black Star doesn't let his gang hang around headquarters much. The way he did before was to have them show up one or two at a time, at certain intervals. He's probably issued all his orders and has quit for the day."

One of the other deputies startled them.

"Here's a little trap door—and a tunnel!" he said.

Sheriff Kowen hurried to the corner. The deputy had spoken the truth. There was a small trap door in the floor, and when it was opened the mouth of a narrow tunnel was disclosed. Sheriff Kowen issued his orders rapidly. Into the tunnel they went, flashing their electric torches, revolvers held ready for instant use.

They followed it a distance of a hundred feet—a dusty tunnel that twisted like a serpent. They came to another small door, finally managed to get it open—and stepped through the thick wall into the alley!

"So that is it!" the sheriff exclaimed. "That is how the woman got away from the house without our seeing her! Careful, now! We'll go back and see that everything is as we found it. I've got a little plan that will be a winner!"

Back they went through the tunnel. They closed the door, saw that the rugs were in place and that everything in the basement was as it should be, and went up the flight of steps.

They made sure that nothing in the house had been disturbed, went outside, and found that the front door had not been much damaged. One of the deputies locked and bolted it on the inside, then got out through a window.

"We'll hope that none of his gang has seen us around here," the sheriff explained. "I've got to let the police in on this, but we'll get the credit, all right. I haven't men enough! We'll have deputies and police scattered all around this place to-night, and we'll nab anybody that goes into this cottage, either by the front door or the alley tunnel. We'll be waiting for Mr. Black Star at the National Trust Company's place, too. The police can help, but we'll get the credit! And when we get that crook back in jail——"

Sheriff Kowen did not finish the sentence, but some of his deputies grinned. They realized that the master crook would be in for a bad hour when he was once more behind the bars. Sheriff Kowen knew how to punish prisoners who tried to escape.

"The big crook isn't as clever as he was before," the sheriff said. "I guess those few months in jail have dulled his wits. If we can catch some of those whelps that worked the game on us and got him away, I'll be highly gratified. I won't need much help when it comes to teaching them a lesson!"

Once more his deputies grinned. They walked to the corner, received fresh orders there, and scattered. Sheriff Kowen engaged a taxicab and ordered the chauffeur to take him to police headquarters with the greatest possible speed, traffic regulations notwithstanding.

He found the chief of police there, and Roger Verbeck in conference with him. Verbeck's big roadster was at the curb, and Muggs was at the wheel. Kowen grinned at him as he entered the building.

"So here you are!" the chief greeted him. "You've got a nerve to show your face after letting the Black Star get away from you!"

"Oh, I don't know!" Kowen said, smiling at them. "Have you gentlemen done anything?"

"What can we do except wait until he pulls off a stunt, and then go after him?" the chief demanded.

"Go after him first! That is what I did."

"Oh, did you?" asked the chief mildly.

"With some measure of success," said the sheriff modestly. "I have discovered the Black Star's headquarters. I have seen some orders to his gang that he left scattered around his table. I found nobody at home when I called, and have every reason to believe that the crook and his gang don't know they have been located."

"Where is the place?" Verbeck asked.

The sheriff told him.

"Possibly you are right," Verbeck said. "But the Black Star is a tricky individual, remember. And the orders are——"

"At midnight to-night," said Sheriff Kowen, trying to retain his modesty, "the Black Star's gang will try to loot the National Trust Company's vaults. Now, let's get down to business!"