But, for a time, Fritz seemed satisfied with the demonstration he had made.  Perhaps he had killed some of the wounded, for not all of them had been brought in.  Perhaps he had only further mutilated bodies that had long since ceased to be capable of movement.

And so, over the dark and bloody ground, Blake and his chums made their way.  In a little while they would be in comparative safety, for their friend the sentry had told them there were no regular trenches near the little hollow where once had stood a machine-gun emplacement and where the boys now hoped to find their precious war films.

But their journey was not destined to be peaceful.  Once more the flaring lights went up, and again came the heavy firing.  Again the boys crouched to get below the storm of bullets, and again they escaped.  But a groan and a cry of anguish, from somewhere on their left, told them some poor unfortunate had been put out of his misery.

They waited a little while, and then again took up the perilous journey.  Presently Blake, taking a cautious observation, announced that they were in comparative safety, and might walk upright.

“Where’s the hut—­or whatever it is?” asked Joe.

“Down in that little hollow, I take it,” said Blake.  “We can’t see it until we round that little hill.  Maybe we can’t see it at all, for it may not be there,” he added.  “But we’d better go slow, for it may be there, and there may be some one in it.”

“Secor and Labenstein, perhaps,” murmured Charlie.

“Perhaps,” agreed Blake.  “If they are——­”

He did not finish, but his chums knew he meant there might be a desperate fight.

A little later, having proceeded cautiously, the boys made the turn around the little hill that had hitherto hidden from view the hollow of which the American sentry had spoken, and then they saw in the light of the stars what seemed to be a tumbled-down hut.  As a matter of fact, it had once been a concrete dugout, where a machine gun had been placed in order to fire at the French and American lines.  But in the heavy fighting of the past few days this place had been captured by an American contingent.  They had destroyed the gun and killed most of the crew, and the place had been blown up by a bomb.  But the fierce waves of Germans had surged back over the place, driving out the Americans who, in turn, captured it again.

Just now the place was supposed to be deserted, being of no strategic value, and in a location that made it dangerous for either side to hold it.

“We’ll take a look in there,” said Blake, when they had drawn near and had discovered that the ruins of the concrete dugout had been covered with brush, to “camouflage” it from spying airmen.

They approached cautiously, and, as they did so, they became aware of a faint light coming from the ruins.  So faint was it that at first it seemed no more than the reflection of the stars, but a long look showed that it was a light from within, but carefully screened.