He felt a sense of relief at this and quickened his pace. He turned a corner, near a dark building, where the shadows were gloomy, and, as he did so, a man stepped from the doorway.

“Is that you?” the stranger asked in a low tone. Larry did not know what to reply. At that moment the man caught a glimpse of him, and muttering a hasty “Beg pardon,” he slunk back into the darkness. Larry hurried on, and, a few seconds later, looking back, he saw the man again come from the shadows and join the fellow who lived below the Dexter apartments, and who had been following our hero.

“Two of ’em,” murmured the boy. “I think they must be up to something, but I hope they’re not after me.”

Almost unconsciously Larry quickened his pace, and a little later he found himself at the apartment house where he lived. The men were nowhere in sight, and Larry concluded they had either delayed on the road or else that he had walked much faster than they had.

No one was up as he let himself into the small flat with his latchkey. His mother called to him from her bedroom to tell him there were some crackers and milk in the cupboard, as Larry was often hungry when he came in.

“And look out for tacks in your room, Larry,” his mother went on. “I took the carpet up in there to-day to clean it.”

“All right, mother,” replied the boy.

He ate a light lunch, and prepared for bed. He heard the persons living on the floor below enter their apartment, and then began that curious roaring sound again.

“I’d like to know what that is,” Larry murmured to himself. “It’s queer they should be carrying on some sort of business and only at night.”

He went on into his bedroom, thinking over the problem. He was recalled to earth very suddenly as, in his bare feet, he stepped on a loose tack.