"Well, I'll see you again when necessary," the stranger called to Mr. Dent. "Good-night."
"Good-night," replied Frank's uncle, as he went into the house and shut the door.
Frank waited until the stranger was out on the path in front of the house. Then, keeping as much as possible in the shadows, the boy followed. He stole along, walking on the sod to deaden his footsteps, and soon found himself on the main highway. Just ahead of him he could see the figure of the man. He tried to see if he knew the stranger, but it was too dark.
"But I'll find out where you go," Frank declared to himself, "I'll get on the track of this mystery sooner or later, and I guess I've got a good start now."
All unconscious of being followed, the man hurried on. He seemed to know his way, for, though it was dark, and the path was uneven, he kept on at a good pace.
Frank was drawing closer, in the eagerness of his pursuit. He was not as careful as he had been to walk on the sod, and, after he had gone about half a mile, the boy suddenly stepped on a loose stone which made him slip. The sound was heard by the stranger, who was about one hundred feet in advance, and he turned quickly.
"Who's there?" he asked sharply.
Frank did not answer.
"Who's there?" the man inquired again, and there was menace in his tones.
Frank crouched down to get in the shadow of a big tree.