It was half a mile back to the southern side of the hill where the bloody engagement of the morning had taken place and a like distance to the little plot of ground in the corner of a field where some of the American dead were buried. Clem and Private Martin easily found the captain’s resting-place.

Some sappers were still at work, and a slightly wounded staff-officer of the marines had been detailed to keep record of the burials. One fellow, his identification number and all papers about his person missing, had not been recognized nor interred. On the way back Clem glanced down at this unfortunate.

“It’s poor Giddings!” he exclaimed.

“What? Not that joker in your company?” protested the officer.

Clem nodded; Martin confirmed this. The lads helped to lower their comrade into his grave and stood with bowed heads during the brief reading of the burial service. Then they went into the field near by and made two wreaths of poppies and daisies to hang on the wooden crosses over Giddings and the captain.

The shadows were growing long; the two “Leathernecks” had quite a distance to travel in the return to camp. For a little way their road lay along the foot of the hill around which a well beaten track had been made by motor cars and artillery. Now and then they were met by ambulances plying between the dressing station west of the hill and of the last battle-field where the marines and regulars had repulsed the German advance. Some of the cars detoured part way up the hillside by a farm lane, on the slopes to seek further for wounded that might have been overlooked.

The driver of a passing ambulance, returning from the dressing station, offered to give the boys a lift and they accepted gladly. They ran on for less than a fourth of a mile when something got out of order with a spark plug which they stopped to replace, just beyond the lane turning up the hill.

“Be only a moment,” the driver said. “I’ll get you fellows right by your camp in ten minutes.”

“Plenty of time!” both said and, while Martin aided the driver a little, Clem walked to an opening in the thicket and gazed up to where, in the morning, he had seen such bloody work with rifle, pistol and bayonet.

Another ambulance came along the road. It seemed to Clem that he had heard the motor start somewhere back under the hill, though there could be nothing strange in that. There was an unusually large Red Cross in its patch of white on the side of the long, low car, and the machine glided along as though it possessed great motive force but was held down in speed. Two men were in the seat. When the car reached the lane it swung in and, without apparent slowing, ascended the grade, stopping about half way up. A few yards beyond it was an army ambulance, its driver walking away across the slope.

Clem’s very brief glance at the driver of the Red Cross car had caused him to start and wonder. He hardly knew why he gazed after the car with an unpleasant feeling, and then, in order to watch its movements, crossed the road and swung himself up on a branch of a low tree.

There were no other cars on the hill and apparently no other people, but the army ambulance man. Clem was cogitating:

“Now, can’t I think where? What had Don Richards said only yesterday? Spies? But would they dare again to come here boldly and—” his thoughts were cut short.

A man got down from the long, low car and quickly went to the other machine. He paused and looked about for a moment, then raised the hood and seemed to be working rapidly. He put down the hood and returned. Then the Red Cross car moved on rapidly up the hill to the far end of the lane, where it turned across pasture ground and veered about among the rocks and thickets, stopping presently on the south-east slope.

“Fire and flinders! It is—it is!” exclaimed Clem. “They wouldn’t dare to go so far east and expose themselves to the guns unless the Huns knew and approved of it.”

The boy dropped to the ground and, taking pad and pencil from his pocket, wrote the following:

This sheet he folded, addressed, and handed to his companion, Martin. The ambulance had a new spark plug and was ready to start.

“Give this to the lieutenant as soon as you get in,” Clem said. “Now, please don’t ask any questions. I’m on an expedition the captain ordered yesterday and the lieutenant knows about it. You might tell him I said so. And, by the way, got any extra cartridges for your pistol? I might need them. I left mine in my kit. Will pay you back when I get back.”

“Maybe I could help you,” began Martin, but Clem backed off.

“No; I can handle this. Nothing much. When I come in I think you’ll see me bringing some Heinies along—pretty soon, too.”

Clem alone, hurried up the hill by the lane. He had but one purpose. His mind was singularly free from any thought of strategy as he went straight to the seat of the trouble. He meant simply to arrest these men and prove their guilt afterward. He reached the army ambulance and saw the driver returning with a wounded man’s arm over his shoulder. This soldier could walk, but he had been shot through the shoulder and had lain unconscious for a time in a shell hole, where he was overlooked. Clem recognized him as a member of his own company. The man smiled and tried to salute.

“Driver, I’ll help this man along. I think when you look at your engine you’ll find something wrong with it. I saw it done—from the road down yonder.”

The driver raised his engine hood. “Well, I should say! Look at that; will you? Every plug wire cut away and gone and the plugs smashed. Do you know who did this?”

“I think I can introduce you to the parties responsible. They’re right up there on the hill now,” Clem replied; then turned to the wounded soldier. “We want to get you in right away and—”

“You let me rest here a bit, Corp. I won’t be any worse off and you go and get those devils. I bet they’re Heinies, drat ’em! I’d like to know some more of them are going the long road, even if I go the same.”

“You’re going to be all right, man.”

“Not on your life, Corp. Never. A fellow always knows when he’s got his for good and all!”

“Don’t believe it,” said Clem. “We’ll take you to the dressing station in that car of theirs shortly, unless another ambulance comes up here. Then you’d better go with it. Now, then, Mr. Driver, you look pretty husky. Feel like having a scrap?”

“I could cut the heart out of the weasel that disabled my car! That is if it was just ‘rough-house.’ I expect he’s got a gun with him.”

“Likely enough—haven’t you?” asked Clem.

“Why yes—in the car—army pistol. But I guess I’m not much at using it. I’m better with a knife. It’s either the gun or me, but I can’t hit a barn door up against it. I can shoot with a real gun, though. I’ve hunted and shot deer.”

“Well, then, bo, all you’ve got to do,” suggested the wounded man, “is to chase back to that shell hole and get my rifle. She’s there; I forgot to fetch her. And she’s a dandy old pill-slinger, too, believe me.”

Ten minutes later the two young fellows went up to the end of the lane and turned sharply to the right, as Clem had seen the suspected Red Cross car do. It was now growing dusk, though the boys could easily make their way across the field. Clem had noticed a bunch of trees taller than those around on the edge of the woods below the summit of the hill, and that the top of one of these trees was partly cut off and hanging: the work of a shell. It was beyond this spot that the spies’ car had stopped.

“We’re getting there,” whispered the driver. “The Heinies are liable to send some whiz-bangs over here any time.”

“I hardly think so while that fellow is here,” Clem said. “We’ll see if I’m not right pretty soon. We’ll have to risk it, anyway.”

“Go ahead; I’ve risked more than that more than once.”

“What is your name?”

“Duncan. I’m from Maine. What’s yours?”

“Stapley. Marines. I’m from Pennsylvania. Go easy now; we’re getting up near the place and they’ll likely be watching out for somebody. Let’s wait until it’s a little darker, then sneak up. I have a hunch those chaps are on this side signaling information to their friends over east.”

The darkness grew thicker and gave way to night. The watchers had found shelter, both against possible German shells or discovery, behind a boulder where they crouched for several minutes. No shells came that way, though the booming of cannon not very far away to the east and northeast showed that the Huns were awake and replying to the constant cannonading of the French and Americans. All around the boys it was as quiet as any night in early summer. Once, overhead, they heard the call of a night bird and once the twitter of some small feathered citizen disturbed in its slumbers in a thicket. There was the squeak of a mouse or shrew beneath the turf almost at their feet. In a whisper that could not have been heard twenty feet away Clem told his companion what he suspected, from his recollection of the doubtful ambulance driver’s face and from Don Richards’ brief account of the signaling near Montdidier. After what Clem had seen here and the injury to the army ambulance, there was enough to satisfy Duncan that they had Hun spies to deal with.

“I’m going to get up and take a look round,” he said. “Going to be an old dead tree; it’s a trick we Indians pull off to fool moose. You see I’ve got a little Indian blood in me. Fact. Proud of it.” And with that Duncan crawled up on the boulder and slowly stood up, his arms extended crookedly, one held higher than the other. Thus he remained for several minutes. Then he came down, even more slowly.

“Say, pard, you’ve got the dope. They’re up there all right, about two hundred yards, and they’re signaling. There’s a light going up and down, bull’s eye, turned away, but I could see the reflection on a rock.”

“Well, we’re here to stop that and get those fellows,” said Clem. “Shall we rush them?”

“No, no! We’d only give them a fine chance to bore us full of holes. They don’t want to be surprised, you can bet. But we can stalk them, as we do bear on high ground, and work the bird call so as to make them think nobody’s around in our direction. Are you on?”

“I am! Say, I guess you are Indian all right. You lead off—and I’ll follow and do just as you do, as near as I can.”

“Only be careful where you put your hands and knees. Don’t crack any sticks nor roll any stones. Ready?”

Clem wondered at first whether the method would prove successful. It loomed up like a large undertaking, considering the distance. Would it not be better to just march right up on the spies and trade gun-fire with them, if need be? But the farther the boys progressed the more Clem became convinced that this was the only means of surprising the enemy. The nature of the ground was such that any one walking boldly up could have been seen first by the spies, and held up or shot. Fortunate, indeed, was it that this fellow Duncan was on the hill. Truly a wonderful chap when it came to this sort of thing.

Slowly they went, on hands and knees, for another fifty feet or more, stopping every little while to listen, and Duncan made a soft twittering sound exactly like the little bird in the thicket below. Presently he rose cautiously to take a look and get the bearings, after which he turned and put his lips to Clem’s ear.

“Man on watch about a hundred feet from us, sitting on a rock. He don’t look this way. I think I’d better edge off a little and work around so as to come up on the other chap, and you work up nearer this one, behind the thicket. When I yell he’ll turn and then you’ve got him. Wait till I yell.”

There is little doubt that this plan would work out well. The German mind can not cope in matters of woodcraft and ambush with that of an American backwoodsman. Duncan wormed himself away and Clem could not detect a sound made in his progress. Hardly more than fifteen minutes would be required for him to gain his object, but in less than five minutes a whistle sounded up the hill. The watcher ran that way and there was the buzz of a self-starter and the whir of a motor. Before the bushwhackers had time to collect their senses the long car, with its lights on, was running back across the field.

Duncan joined Clem. “Rotten luck! But glad you didn’t shoot. And say, they’ve got to go slow over and around those rocks. Can’t we head ’em off if we go down the hill straight toward the foot of the lane? How’re your legs?”

“I’m with you!” announced Clem, and together, with the easy, long-stepping lope of the runner trained in the woods, the two set off, leaping over the obstacles in their way, dodging around boulders and thicket patches, and making good time in spite of the uneven ground.

But they had not covered a third of the distance and had several hundred yards yet to go when they saw that the chase was hopeless. The car had made far better time than they had believed possible and when it reached the head of the lane it turned and shot like an arrow down the hill.

The boys stopped and gazed in bitter disappointment after the retreating foemen.

“I wish we had sailed into them up yonder,” Clem said.

“Gettin’ shot ourselves would have been worse than this,” Duncan argued.

“Say, look, they’ve stopped! About where your car is!” Clem exclaimed. “Maybe we can—”

Duncan raised the army rifle as though to bring it into position for firing. “If it wasn’t so blamed dark I could get ’em,” he declared. “Anyway, I can make a try.” But Clem stopped him.

“Hold on, man! You may hit the wounded man there!”

“Blazes! Never thought of it. Can’t risk that. Couldn’t stop ’em, anyhow; not in a million shots, with only their lights to shoot at.”

“There they go on again. We’re licked this time,” Clem said, mournfully. “Come on; let’s get back to the lane. I’ll help you make that poor chap comfortable. Then I’ll go down and try to get another ambulance. I’ve got to get back to camp pretty soon. Say, it’s going to be tough to have to admit we couldn’t arrest those spies. It’s what I stayed out for and sent word to the lieutenant that I could do. He’ll be sore, and Martin will rub it into me for a month. Say, those spies have put out their lights now.”

Duncan mumbled something about their running on with lights out to avoid being recognized. He hoped they’d run into a shell hole and break their blamed necks. The young down-east woodsman was grievously put out not to avenge himself on the men who damaged his ambulance.

Not another word was exchanged between the two youths while they were crossing the open ground to the lane. They reached and turned down the well-worn road a little above the ambulance.

“He’s asleep, I guess,” Clem said, glancing at the soldier lying on the cot that Duncan had spread for him. The ambulancier went over and stooped down to look at or speak to the wounded man. Then he straightened up with a jerk and stepped back. Though his nerves were of steel after the many bitter experiences following battles, raids, artillery fire and gas attacks, he must have had a sharp prod at the sight that met him. It is one thing to see men killed, maimed, blown to pieces in fair fighting, but quite another thing to find one foully murdered outside of the area of fighting.

“Killed!—stabbed! They’ve killed him! Those—those devils!” His voice was thick with rage.

Clem could only weakly repeat part of this—it was too horrible for mere words. Instinctively they both turned to gaze down the lane again toward where the spies had fled. And suddenly, from the bottom of the hill, the two bright lights of an approaching ambulance glared at them ominously.