AS Tom, in the gray of the breaking dawn, came pounding into the lines which surrounded the thousands of sleeping soldiers, he nearly precipitated himself upon the out-thrust bayonet of a sentry whose call of halt he did not hear.

His breath coming and going in quick, sharp gasps, Tom managed to give the countersign, adding, “Sergeant Walton, Company C.” The sentry lowered his rifle and Tom proceeded; but a few yards further on he was compelled to repeat the process. For once he wished that all sentries were asleep on their posts.

At brigade headquarters he encountered a man who refused to get excited, and who demanded to know in detail what it was Tom wanted before he would waken his own sergeant to see if the message could be delivered to the general.

“I tell you,” Tom blurted out, in rising tones, “the life of every man here is in danger. This place is likely to be blown off the map any minute. The whole place is mined. I’ve just seen the bombs—scores of them—in a big underground chamber directly under the town. I’ve got to speak to someone in authority.”

“What’s that you say,” demanded a staff major, suddenly appearing on the scene. He had heard the last few words, and as he peered into the face of Sergeant Walton, who immediately came to a salute, he seemed instantly to sense the seriousness of the situation.

Briefly as possible Tom repeated his startling information. The major rattled off some orders to the sentry and a sergeant who had appeared, then left suddenly, telling Tom to wait right there.

In an incredibly short time the brigadier general, followed by most of his staff, emerged hurriedly from a dug-out.

“You are certain of this?” the general demanded sternly.

“Absolutely positive,” Tom answered. “I fell into the mouth of the cave myself, in helping to capture the German who had just come out of it, and when I found that it was a long tunnel, leading directly northward toward this spot, I led the way through it. We came upon a large underground chamber practically filled with big bombs, all connected with a cable. I should measure the distance we travelled as bringing that chamber almost beneath where we are standing now.”

Had Tom himself thrown a bomb into the midst of the gathered staff members it hardly could have caused greater consternation.

The general waited for no more. He barked a dozen orders to as many different officers in rapid-fire succession.

“Come with me,” he instructed Tom and those officers who had not yet been charged with special duties. He led the way quickly to a dug-out further down the line. Before they reached it bugles were sounding, men were tumbling out of their blankets, rubbing their eyes and looking about sleepily. Staff officers were shouting the orders for immediate movement. Officers and men who heard, looked around hurriedly for signs of the enemy.

In the dug-out the general ordered one of the several men sitting at telephone instruments to connect him immediately with the commanding officer of the nearest unit of Engineers.

To this officer he indicated as definitely as he could the position of the mouth of the tunnel, and ordered him to be there as quickly as possible.

“To dig out mines,” he summed up. “They’re already connected up, I believe.” And seeing the first of the thousands of men under him already on the move for designated points beyond the danger zone, he took a part of his staff with him, and with Tom in the lead, set out at a vigorous double-quick for the point where George Harper still was guarding the man whose movements indirectly led to discovery of the mines.

Meanwhile Ollie had encountered even greater difficulties than Tom in his search for the commanding officer of the Engineers, for although he went directly to the wood, he found only small squads at work there, the main body having progressed in a circling movement to the northward of the town, to prepare the pathway for the day’s advance.

When, after the greatest difficulty, he finally did locate the headquarters of the colonel, he arrived there just in time to see the latter and his aides departing at the head of a hundred men.

Saluting a lieutenant, Ollie started to tell him his story, but was cut short with the information that the news already had been received and they were then on their way.

“But you arrive at a good time,” the lieutenant added quickly, and addressing a superior he informed him that Ollie could take them directly to the spot.

And thus it was not without a justifiable feeling of being of some real importance that Ollie was called to the colonel’s side, and walking beside that officer, to direct the way, was plied with questions as to the discovery. It was little enough that Ollie could tell, for Tom had given him but a bare outline of the danger that confronted the troops. Nevertheless the colonel thanked him warmly, not forgetting to add a word of praise for all three of the lads after he had been told how it happened that the mouth of the tunnel had been discovered.

“And you got your man after all?” he asked, when Ollie had finished, having touched but lightly upon the fact that all three had at one time dropped off to sleep.

“Yes, sir, he’s wounded,” the lad responded.

“Well, he’ll probably wish he had been killed outright,” was the colonel’s cryptic comment.

As if in reply to that remark, German guns far to the north let go a salvo of shells, several of which fell uncomfortably near. The colonel glanced in the direction from which the projectiles seemed to come, but his pace never wavered.

“Fritz seems to be out of bed, anyway,” was all he said, as another shell exploded not a hundred yards to the left of them, throwing up a veritable geyser of dirt and rock and splinters of steel.

As they came over a little knoll, Ollie pointed out where the tunnel entrance was, and the colonel raised his glasses to get a better view as he walked.

Approaching, from an about equal distance beyond the spot where Harper and his prisoner sat, were the general and members of his staff. It was when both parties were within fifty feet of the entrance to the passageway that a shell exploded with such violence and in such proximity that it knocked both Harper and his prisoner on their backs. For a moment everyone thought they had been killed.

It was Ollie, who with a feeling of dread, realized the real damage that that shell might have done; and as misfortune would have it his surmise was right. It had landed directly over the tunnel, a few yards beyond its entrance, and with such force as to cave the whole thing in!

As the general and colonel arrived almost simultaneously, the situation and its necessities became clear. It required but a moment’s investigation by one of the members of the Engineers Corps to verify the fact that the passageway had been effectually blocked by a great wall of earth caved in by the shock of the exploding shell.

The general held a short consultation with the colonel of Engineers, and then called both Tom and Harper to them.

“Young men,” he said, “we are going to place a great deal of reliance upon your judgment and sense of direction. A straight line drawn from the entrance of this tunnel to the spot where the shell caused a cave-in shows that you were right in saying that it ran almost directly north from where you started. You are sure it takes no turns?”

“Not until the very entrance to the bomb chamber,” Tom answered quickly; and Harper corroborated him.

“Very well,” the commander went on quickly. “If that is true, then we are saved some unnecessary labor. It is not likely that we could dig directly into the tunnel from any given spot, but we will proceed directly northward to a point which you consider near to the chamber, but yet a safe distance away, then try to effect an entrance.”

And with competent engineers directing a true northward course, they proceeded rapidly toward Thiaucourt.

Tom, who had been considering the distance carefully, came to a halt and saluted. “I would suggest, sir, that perhaps this is as near as is safe to begin the digging.”

“Very well,” the general replied, and nodded to the colonel.

A moment later fifty men with spades were lined up before their commander for instructions. He marked the spot where the tunnel might be, and then, at right angles to the direction they had walked, or almost directly east and west, he established an imaginary line.

“Dig along that, working toward this point at the centre,” he ordered. “Somewhere along that line you should strike the tunnel. Proceed with care after you are six or seven feet deep.”

Every man there had a fair idea of what depended upon cutting the connection to those bombs before, somewhere to the north, a German hand reached for a switchboard and turned on the current that would cause a holocaust. Also, they knew that they were about the closest in proximity to those hidden mines, so there was no lack of incentive for all the speed that strength could muster.

Dirt flew out of that ever deepening and lengthening pit in a constant cloud, piling up a high trench work on either side. But despite the care to which they had cautioned, it was the muffled exclamation of surprise from a man suddenly dropped downward with a great accompanying scraping and crashing of earth, that heralded the discovery of the tunnel.

The general and colonel both smiled their congratulations to Tom and Harper at the accuracy of their report. At the same time spades worked with feverish haste, the man who fell into the tunnel was extricated undamaged, and the hole was rapidly widened to let two or three in at one time. Then another halt was ordered.

The colonel spoke.

“A short distance to the north of us is an underground chamber supposedly filled with highly explosive mines. They are wired and, it is believed, are directly connected up with the German lines. Apparently the enemy has been waiting for the concentration of a large number of troops here before touching off the mines. He may decide to do so at any moment. I want volunteers to go into that chamber and sever the cable connection.”

Instantly every man present stepped forward. The colonel’s face glowed with pride, and the general nodded approvingly. This was the spirit which made America invincible! One looking at the general’s fine countenance saw there satisfaction, absolute assurance. A nation could not fail with men like these! And they but typified the entire United States army.

The colonel rapidly picked half a dozen of the men he thought best fitted for the hazardous task at hand, and under the guidance of a clean-cut captain they dropped into the tunnel and disappeared from sight.

Agonized moments dragged by, and scarcely a word was spoken. The colonel had suggested that all hands move further away from the danger zone, but as he and the general gave no evidence of doing so themselves, none of those present, no matter how they felt about it, showed the hardihood to seem to want to escape, when a little group of their pals probably at that very moment were struggling with the heavy cable which at any time might be charged with the death-dealing current.

Every man present held his breath when the captain suddenly dashed into sight, quickly lifted himself to the ground, and, grabbing a spade from one and a pair of rubber gloves from another, started back over the line which the tunnel followed to the bomb chamber.

“Connection’s cut, but I want to see something,” he told them.

As he began digging they gathered in a wide circle about him. Presently he struck a hard metallic substance. With a wave of his hand he requested them to get to a greater distance. A few more cautious jabs with the spade and he stooped over, gripping something with both hands and tugging upward with all his strength. The blood rushed to his face and the veins on his neck and forehead stood out, but after a little the thing he was pulling began to give way.

It was the severed cable. With a final jerk he pulled the loose end through the ground, and all hands could see where the cut had been made. At last the terrible menace was over. The captain looked triumphantly at his superiors. He laid the cable on the ground.

“Don’t go near it,” he cautioned, “because—”

The sentence was never finished. There was a sudden sharp crackling, a gasp of exclamations from the throng, and a shower of sparks shot into the air from where the severed cable end lay upon the ground.

The Germans had turned on the current, but they had turned it on a moment too late!

The narrow margin by which a terrible tragedy had been averted was obvious to all. They stood about, awed and silent, watching the deadly current expend itself in a harmless sputter.

The general himself was a man of few words. He summoned the lads to him.

“Young men,” he said, “I congratulate and thank you. You have saved an army. It will not be forgotten.”

And the three youths flushed deeply as a lusty cheer went up from the men gathered about them.