"The game's up at last!" he hinnied. "I saw it was you kids, and I couldn't resist giving you a scare. I don't know that I meant to let you find me out, though. If I hadn't tumbled I'd have got off. What have I been masquerading like this for?" He suddenly looked grave. "That's a little business of my own. I wanted to find out something, and I thought I'd raise a rumour that might keep the woods clear of ordinary trespassers. How did I do it? Easy enough, some theatrical togs I had by me, and springs on my heels." "We've seen you before in this rig-out," volunteered Anthony. "When?" "When you pounced on Mr. Hockheimer and stopped him burning a letter." "We were there watching," echoed David. "Oh, have you got the paper still? It was mine!" cried Pamela breathlessly. It was Captain Harper's turn to be astonished. "Yours! What had it to do with you?" he asked sharply. Pamela and Avelyn explained between them. He took a cigarette from his pocket and lighted it as he listened. "This is quite another development," he commented. "Part of the paper was burnt. I couldn't understand the drift of it." "Have you got it still?" besought Pamela. "No, I gave it to my superior officer. But if it is of such importance as you say I could get it examined on your behalf. I'll speak to my Colonel about it. It's worth investigating." "Pam!" said Avelyn impulsively, bending her head and whispering in her friend's ear, "do you know, I believe it would be the best thing in the world to tell Captain Harper what you've told me this afternoon. He'd know better even than Mother what you ought to do." "You tell him--I daren't," faltered Pamela. If Captain Harper had been astonished before, he was doubly amazed now. "Great Scott! It's the very thing I've been on the scent of for this six months!" he ejaculated. "We guessed there was a wireless somewhere over here, but never could locate it. And to think I owe it to you kids! Pamela, you're a true loyal little Englishwoman! I think you'll find you'll pretty soon be rid of that precious uncle of yours." "What must I do about it?" asked Pamela, who was half crying. Captain Harper did not at once reply. He seemed cogitating. Then his face cleared. "Nothing at present," he replied. "I pledge you all on your word of honour to mention this business to nobody. We'll leave the wireless where it is, and get the messages if possible--that's our game! Pamela, could you manage to learn the Morse code if I taught you?" "I'd try." "I'll undertake you'd soon learn it. Then what you've got to do is to listen at the receiver and report to us. I can tell you, you may be working an uncommonly important little bit of business. Don't cry, child! The fellow is only your uncle by marriage. He's no blood relation of yours. Think of your father! You're doing your duty by your country as every true-born Britisher ought." CHAPTER XXI Pamela's Night Walk