“Bah!” ejaculated Frank savagely; and he stepped in, raising his right hand, and making a quick menacing gesture, as if to strike the man a heavy blow across the face.

Taken thoroughly by surprise by Frank’s feint, the spy made a step back, when, quick as thought, the boy seized the handle, drew it to him, banging the door and turning the key, and stood panting outside, his enemy shut safely within.

“Here, open this door!” cried the man; and he began to thump heavily upon the panels. “Quick! before I break it down.”

“Break it down,” cried the boy tauntingly. “How clever for a spy to walk into a trap like that.”

There was a moment’s silence, and then—as if long coming—something which resembled the echo of Frank’s angry stamp on the floor was heard, followed by a heavy bump. The man had thrown himself against the door.

“He won’t break out in a hurry,” muttered the boy; and he ran to the staircase, and in familiar old fashion seized the rail, threw himself half over, and let himself slide down the polished mahogany to the first floor, where he rushed in, closed and locked the door of the room, hurried excitedly to the picture door of the closet, the portrait of his ancestor seeming to his excited fancy to smile approval, and, as he applied his hand to the fastening, he heard faintly a noise overhead. The next moment a chill ran through him, for the window of his bedroom had evidently been thrown open, and a clear, shrill whistle twice repeated rang out.

“That means help,” thought Frank, and he hesitated; but it was now or never, he felt, and opening the closet, he snatched the desired letter from the shelf, thrust it into his breast, and closed the closet once more.

The whistle was sounded again, and a fresh thought assailed the boy.

“They’ll seize me, search me, and take the letter away. What shall I do?”

He ran to the window in time to see a strange man climb the rails, and drop into the garden, run toward the house, stoop down, and pick up something.