Staggered, the men all stopped short in their tracks. An instant later there was a second explosion. There was a ripping, splitting sound, and the whole side of the building fell out. The air was filled with bits of wood and plaster.

"Keep away from that house!" shouted Sergeant Riley as one of his men darted forward. "Do yez want to get killed?"

A minute later flames appeared, and the red and yellow tongues of fire began to play around the window frames. Black smoke curled from every opening. It was plainly to be seen that the house was doomed.

"Look!" cried Hugh suddenly. "There goes a man!"

Without waiting to see what the others were going to do he dashed off in pursuit of a figure which could be seen scuttling away through the trees. Two of the detectives joined in the race and one of them fired two shots from his pistol at the fugitive. In reply the man suddenly wheeled and shot once at his pursuers. Bob heard the bullet whine past close to his head. He also had caught a fleeting glimpse of the man, and one look was enough to convince him that it was the fake detective with whom he and Hugh had struggled that morning.

A moment later the man was out of sight, Hugh and the two detectives still after him, shouting and calling to him to halt. Meanwhile the fire in the house roared and blazed.

"She's a goner," said Sergeant Riley. He stood beside Mr. Cook and Bob as they watched the burning building.

"I guess she is," remarked Mr. Cook. "There's nothing we can do."

"Nothing," agreed the sergeant.

"It's not much loss anyway," said Mr. Cook.

"No loss at all," exclaimed Bob. "It's a gain if anything, for it makes one less place for spies and plotters to meet in."

"But any evidence that might have been in there is destroyed," said Riley.

"I never thought of that," said Bob. "That's probably why they burned it."

"Was that your detective running off through the woods?" asked the sergeant.

"It certainly was," said Bob. "I guess he was one of the gang after all.
I suppose they left him behind to watch us."

"Then why did he let you get away?" his father replied.

"Probably he thought it would create less suspicion," said Sergeant Riley. "He got the paper away from the boys and as long as he thought he could bluff them into thinking he was a detective he thought that was sufficient. On the other hand if he had held them prisoners or anything like that there would have been a search for them and trouble started at once."

"I guess that's right," said Mr. Cook soberly. "However, I hope they catch him this time."

Suddenly a piercing scream startled them. They glanced up to see a white face at one of the windows of the house. All around, the fire roared and the smoke curled up in great clouds. Before they could see who the man was he had fallen back into the room and disappeared from view.

"I'll get him," exclaimed one of the detectives, and without further ado, he sprinted for the burning house. Paying no heed to the warning cries of his comrades he dashed up to the back door and entered, and was soon lost to sight.

"That feller Donovan is a dare-devil," exclaimed Sergeant Riley. "He'll stop at nothing. Why should he risk his life for a man that's as good as dead now?"

"He'll never come out alive," cried Mr. Cook.

"And all for a man who is plotting against the country," echoed Riley. "Here you!" he shouted to the other plain-clothes man. "Keep out of there. The High Ridge police force can't afford to lose more than one man a day." The fourth detective showed signs of wishing to follow his comrade.

"If he does rescue that man it'll only be to put him in jail," said Bob.

"Or shoot him more likely," cried Riley angrily.

Breathless they waited for any sign of Donovan. The fire burned more fiercely every moment, and it seemed incredible that any man could enter that seething furnace and return alive. The air was filled with sparks and blazing embers; the smoke mounted heavenward in a thick column which must have been visible for miles.

Minutes that seemed like hours passed. Hugh and the two detectives returned from their chase. They had not captured their man.

"We followed him as far as the road," one of them reported. "He had a motor cycle there and got away from us."

"We'll get him later, never fear," said Sergeant Riley, grimly. "Meanwhile that crazy man, Donovan, is in the house here trying to rescue some one of them German plotters that showed his face at the window."

The recipients of this piece of news gasped. "He'll never come out," exclaimed one of the men. "Still, he never did seem to care much for his life."

White faced and tense they watched the conflagration. Certainly not one of the men ever expected to see Donovan again. Yet what could they do? As Sergeant Riley had said, it was folly for any one else to follow him in, and so they were powerless. All they could do was watch and hope.

Suddenly a figure appeared at the door. It seemed to issue straight from the hottest part of the fire. On its shoulder was the limp figure of a man.

"There he is!" cried six voices together, and together the six watchers made for the house.

Donovan, for it was he, stood on the charred steps. Sparks and blazing firebrands fell all around him and he tottered uncertainly. Willing helpers rushed to his assistance, but before they could reach him he swayed and fell. He rolled down the step dropping his burden, and side by side the two men lay on the ground. Close by, the wall threatened to fall on them at any moment.

It did not take long to seize both men, and carry them away from danger and a moment later they were stretched out side by side on the grass, a safe distance from the burning building.

The man whom Donovan had rescued, had a face so blackened by smoke and soot that he was unrecognizable. His clothes were scorched and his whole body seared with terrible burns. He was unconscious.

"Is he still alive?" whispered Bob in a low voice.

Sergeant Riley put his hand over the wounded man's heart. "I think so," he said. "Get some water somebody. And look after Donovan."

"There's a spring back there in the woods," exclaimed Hugh. "I have nothing to carry water in though."

"Take all the handkerchiefs you can get," ordered the sergeant. "Fill the hats; you'll lose most of it on the way back, but you'll get some."

Hugh hastened to obey; with him went Bob and two of the detectives. The spring was not far distant, and they soon were sousing the handkerchiefs in the clear, cold water. The hats, too, were filled and those made of felt held the water fairly well. A few moments later they were hurrying back toward the spot where the injured man was lying.

It had been found necessary to remove the patients farther away from the burning building, for the heat grew more intense every moment. Donovan had so far recovered as to be sitting up. He suffered acutely from numerous burns, but otherwise seemed to be all right. The man whom he had rescued, however, still lay unconscious on the ground.

Sergeant Riley now took charge of the operations. He bathed Donovan's face with one of the handkerchiefs and gave him another to suck. Mr. Cook under Riley's instructions poured water from one of the hats upon the other sufferer's face, and then gently sopped it with a handkerchief. As a result of this treatment the soot and grime disappeared and presently it was possible to distinguish his features.

Suddenly Mr. Cook started back in surprise. "Come here, Bob," he cried.
"See who this is."

One glance was enough for Bob. He recognized the man over whom his father was working as Mr. Wernberg.