"I must have been dreaming through the scenes of last night again," Hal muttered drowsily. None of the other men in the room appeared to have heard the sound at all. But now it came again. A shot was followed by a second, then by a third. "Corporal of the guard--post number three!" yelled a lusty voice, though the distance was such that Hal Overton heard the sound only faintly. Crack--crack! Then a bugle pealed on the air, though still Hal's comrades in the squad room slumbered on. Too curious to turn over and go to sleep again, Hal stole softly from his cot and reached an open window on the side that looked out over the parade. There was no moon, but in the light of the stars Hal could see several uniformed men running swiftly across the parade ground to officers' row. "It's no dream," muttered Overton, intensely interested, "for there goes the corporal with the guard. What on earth can it mean?" There was something up--and something exciting, at that, for experienced sentries never fire except in case of need. Moreover, several sentries--no fewer than four--had just fired almost simultaneously. Nor did the corporal and his squad return within the next few minutes. Whatever it was that had resulted in turning out the guard, the need for the guard plainly still continued. "There's no more shooting, anyway," Hal reflected. "I may as well go back to bed." It was some minutes ere he could sleep. When he did fall off it seemed as though only a minute or two had passed when the bugle again pealed. Hal was on his feet in a second. So were most of the other soldiers in the squad room this time. "Why, it's daylight now," uttered Hal, looking astounded. "Of course it is, rook," laughed the soldier whose bed was next to Hal's. "That bugler sounded first call to reveille. Don't you know what that is yet?" In other words the soldier's alarm clock had "gone off." Though all of these men had slept through the call for the corporal of the guard, simply because it did not concern them, every man had turned out at the first or second note of "first call to reveille." Every man dressed swiftly. As soon as he got his clothing on each soldier turned up his bedding according to the regulations. There was some "policing" of the room done. That is, everything was made shipshape and tidy. Last of all, and within a very few minutes from the start, the men made their way briskly to the sinks, where soap and water, comb and brush, put on the finishing touches. A sergeant, two corporals and nearly a score of men were now as neat and clean as soldiers must ever be. "What was that row in the night, Corporal? Do you know?" Hal asked. "What row in the night?" asked Corporal Cotter. "Why, there was a lot of shooting, and a call for the corporal of the guard to post number six." "First I've heard of it," replied Corporal Cotter. "But we'll know before long. Now, step lively, rook, for you're on duty with the rest to-day."