"Sure enough," agreed Billy. "But what is there that they would want to blow up?"
"Maybe some of these red spots are meant to indicate meeting places of the conspirators," suggested Frank. "See, there's a little red cross added here that you don't find in connection with the army and government buildings. But it's queer that that alley should turn up again. I wish I knew what it meant."
"Well, we'll have to let the Secret Service ferret that out," said Billy. "They have fellows there to whom this will be as clear as crystal after they've studied it a little. In the meantime we've got a big enough job on our hands to take care of these prisoners. What are we going to do with them?"
"We've got time to think that over between now and daylight," answered Frank. "For the present we'll make them lie down flat and far enough apart so that they can't talk with each other. Then you and I will stand the first watch and Bart and Tom the next. As soon as daylight comes we must be on the move."
The plan was carried out, although Bart and Tom declared that they had lost all desire for sleep and would keep awake with the others. Frank, however, wanted to have them in good shape when morning came, and the plan was carried out. As a matter of fact, Bart and Tom were fast asleep in five minutes, and Frank and Billy yielded as readily when their turn came.
With the first streak of dawn, the boys were on their feet.
"Doped it out yet?" Bart asked of Frank.
"Pretty well," his chum answered. "I've figured out that we'd do better to try to find our detachment than to go back with these fellows to Coblenz. In the first place, it must be nearer, and then, too, we have the chance of meeting some of the detachment who have probably been sent out to look for us. The sun will give us the general direction and we'll probably hit the camp before long."
"Perhaps some of the prisoners could give us the direction," suggested Bart.
"I suppose most any of them could," answered Frank. "Some of them, no doubt, are natives of this section, though that big red beard comes from Berlin. But do you think I'd trust any of them? Not on your life! They'd only lead us into a trap."