Arrayed in the German uniforms—­the attire of lieutenants—­the three advanced toward where they felt sure the main German entrenchments must be.  Hal glanced at his watch in the moonlight.

“Ten o’clock,” he said.  “Within three hours we should have learned all we need to.  As soon as we reach the German lines we shall separate.  We’ll meet here again at two o’clock.  Is that satisfactory?”

“Suits me,” said Chester.

“Want to lose me, do you?” grumbled Stubbs.  “Never mind, though.  I’ll be here by the time you are.”

“Pick up every scrap of information possible,” Hal enjoined his companions.  “Don’t take the trouble to write it down.  Just impress it on your memory.”

The others nodded their understanding.

The three came now upon a light in the distance.

“Germans ahead, I guess,” Chester whispered.  “Careful and let all further conversation be in German.”

The lad was right.  Advancing two hundred yards farther, the three friends came upon the outlying sections of the big German camp.  Sentinels moved about in the darkness, their forms lighted up now and then by the flare of campfires—­for the night was very cold.

Once they were challenged by a sentry, but when the man looked at their uniforms in the moonlight, he lowered his rifle and passed on.

“I’ll go straight ahead,” said Chester in a low voice.  “Hal, you go north and let Stubbs go south.”

And thus it was arranged without further talk.  The three friends separated.

Walking between the rows of German tents, Chester, after perhaps half an hour, was arrested by the sound of voices in a tent that seemed, in the darkness, to be much larger than the ones which surrounded it.  He paused and listened attentively.

“Then everything is in readiness,” came a voice.

“Everything.  When the French see that we have weakened our lines on the left wing, they naturally will press forward in masses.  The pressure on the right wing probably will be lessened.  Also in the center.  General Petain, in all probabilities, will seek to take advantage of what he will believe is our carelessness.”

“And then?” asked the first voice.

“Why, then we shall push forward in the center and on the right, leaving enough men on the left to make a show of force.  Taken at a disadvantage, the French will be cut off on our left, and our center, sweeping around, suddenly, will envelop them.  As I estimate it, the French wing, which will be thus enveloped, will be 100,000 strong.  It will be a telling blow.”

Chester, while this conversation was in progress, had shrunk close up against the tent.  Now, thinking to gain a view of the occupants, he drew his knife from his pocket and made a little slit in the canvas.  To this opening he applied his eye; and then gave an exclamation under his breath.

In the center of the group of officers in the tent was none other than the German Crown Prince, the directing head of the German attack on Verdun, and son of the Emperor himself.