Whatever errand had brought Rabig to this spot, Tom felt sure that it boded no good to the American cause, and even in the precarious position in which he found himself he rejoiced at the thought that he might be instrumental in unmasking a traitor. While these thoughts were passing through his mind, a German officer approached from another direction. He saw Rabig, and hastened toward him. He greeted Nick coldly, and with an air that scarcely concealed the contempt he felt for the man whose services he was using. An animated colloquy began at once. But unluckily for Tom it was in German. He hated the language, but just then he would have given anything if he could have understood what was passing between the two men. The conversation continued for some time. Rabig handed over some papers which the German officer carefully looked over, using a pencil to follow some lines that seemed to be the tracing of a map or plan. Then he folded them up and put them carefully in his pocket, and after a few more sentences had been exchanged Tom heard the clink of money and saw Rabig tuck something away in his belt. Then the officer stood up and with a curt nod went away toward the bottom of the hill. For some minutes more Rabig remained sitting at the foot of the tree. Then he took money from his belt and counted it carefully. Tom couldn't help wondering whether it consisted of thirty pieces of silver! In Tom's mind a plan was rapidly forming. He looked through the trees in every direction. No one was in sight. From the slope below came the hum of the camp, but no helmets were visible. If Rabig had come through the German lines he had done so by means of a pass. That pass would take him back just as it had brought him through. He must have it in his pocket now. Tom measured the distance between himself and the figure sitting beneath him. Then with the litheness of a panther he dropped plump on Rabig's shoulders. The shock was terrific and knocked the breath from the traitor's body. He rolled over and over. Tom himself was thrown forward on his hands and knees, but the next moment he had risen and his hands fastened like a vise around Rabig's throat. CHAPTER XXI CROSSING THE LINE Nick Rabig was a young man of powerful build, and under ordinary conditions Tom would have had his work cut out for him. But the surprise and the shock had taken all the fight out of the traitor, and Tom's sinewy hands never relaxed until Rabig's face was purple and he lay limp and gasping. Then Tom improvised a gag and thrust it into the rascal's mouth and rapidly bound his hands and feet. When he had the miscreant helpless, Tom rose panting to his feet and looked about him. There was no sign that the struggle had attracted attention. Rabig himself had had no time to utter a cry for help.