"Fact," replied Billy. "I could see it plainly, and behind it I saw the outline of a door. I started to tell you fellows about it, and then I heard one of you shout and I didn't think of the thing again till this blessed minute."

"Well, that certainly was hard luck!" exclaimed Frank bitterly. "Ten to one that's the clue to the mystery. My hunch wasn't a false alarm after all. I've a good mind to go back right now and finish the job."

"Not on your life you won't!" said Bart decidedly. "Not if Billy and I have to hold you back by main force. Why, boy, you're crazy. Those rats have tasted blood, and they're full of fight. And then, too, we haven't any clubs to beat them off. It would be sheer suicide to go in there again to-night."

"Bart is right," acquiesced Billy. "Some other night perhaps when we're in shape for it, but not now. Come along, old man, and use your common sense."

Frank knew in his heart that his friends were right, but it galled him horribly to defer the adventure.

"Well," he agreed reluctantly, "we'll call it a night's work and let it go at that. But I'm only giving it on the promise that we'll try it again. We've never let anything in Hunland get away with us yet, and it's too late to start it now. If I live I'm going to get to the bottom of this."

"Sure thing," agreed Bart. "We're just as keen to clear it up as you are. But this isn't our lucky night. Let's light out for the barracks and fix up these bites."

They made their way back and slipped in as unobtrusively as they could, and after they had cauterized and dressed their wounds they sought to forget their disappointment in sleep.

The next day found them stiff and sore, but this feeling wore off as the day progressed, and when night came they forgot everything in their eagerness to be on the march to hunt for their missing comrade, who had hardly for a moment been out of their thoughts.

The plans for the expedition had been carefully mapped out. The detachment was to travel by lanes and byroads as much as possible, and under the cover of darkness they hoped to avoid observation and comment. Their chief hope of success lay in taking the enemy by surprise, and every precaution was observed to prevent any miscarriage of their plans.