That night Don went to bed with the subject still uppermost in his mind to the extent that it was becoming rather tiresome because barren of results; and beyond any chance of solution. More to relieve his mind than anything else he managed to get Clement Stapley on the telephone quite late and told him of seeing the men, half expecting his partner in the mystery to characterize him as a boob for considering such a thing of sufficient importance to bother him. To his surprise Clem appeared tremendously interested and insisted on their getting together the next morning. Don agreed, hung up and went to bed. He usually slept like a log, the result of good health and a clear conscience, he himself declared, and there could be little doubt of this, but however tightly wrapped in the all-absorbing arms of slumber, the dulling influence suddenly and entirely relaxed an hour or so after midnight. Along with a large majority of the townspeople, according to later evidence, he found himself sitting up in bed and wondering why the house was trying to do a dance and the windows to imitate a drum corps. Then came voices from within, some in alarm, others in quieter comment and the words: “Great fury! Is the house coming down?” from Merrill, next to Don in age. “What was that, Dad?” a younger scion questioned. “An explosion of some kind; two of them!” This from the doctor. “Where ’bouts?” “Yes, where do you think it was, Father?” “Over on the other side of town; perhaps the mills.” “Ooh! Can we go an’ see, Daddy?” This from the baby of the family. “No; in the morning. It’s only two o’clock now. Go to sleep.” “But you’re going, Father; they may need you,” Donald offered. “Yes, and I’ll take you with me.” It was the mills. One building with the office in part, had been utterly wrecked, another had been partly destroyed and one end was on fire. And while the volunteer department and helpers were valorously extinguishing the flames another explosion occurred that hurt two men and flung some others down, Don amongst them. The boy was uninjured, though the jarring up made him see red. But with a shrewdness beyond his years he kept silent as to what he suspected and his ears were keen to catch the talk going on around him. It seemed to be the idea of one and all that this was the work of German spies. Presently, from behind some splintered boxes, they found the half-unconscious watchman and resuscitated him, getting him to talk. He had obtained one good look at the miscreants as they ran away. Don kept an eye open for Clem and as that youth appeared leaping with his father, from a big motor car, he was grabbed and pulled aside. “Don’t say a word about what we know,” Don whispered. “Here’s a chance for us to get right up on top of everybody. It was those two, Clem.” “But, look here, Don, Father ought to know--”