Stickney gave a low whistle. “For the love of Mike!” he ejaculated under his breath. “Let me have a good look at you. Yes, I guess you’re Nick all right, although I wouldn’t have dreamed of it if I’d passed you a dozen times. What’s the matter? Is there anything queer going on here?” Nick nodded. “Very queer,” he answered. “This isn’t the proper time to go into particulars, but I’ll tell you this much. The man in number twenty-two has a room or two to rent in his upper story, and if you’re not careful he’s going to commit a terrible crime this very night. There are reasons for keeping dark, and for not taking him into custody just yet. Will you help me, though, to save him from himself, and to shield his intended victim?” “Sure thing!” was the prompt answer. “I’ll do anything I can. I’d like to know a little more about it, and I’d insist if you were any one else. I can trust you, though, and I’ll keep mum until you give me the word. What is it you want?” “Something very simple.” Nick drew nearer to the house detective and spoke even lower. “Do you get the idea?” he asked, in conclusion. Stickney nodded. “Of course,” he answered. “I can fix that up without any trouble. Is that all you want me to do?” “That’s all,” Nick replied. “Wait for ten minutes after I get back to my room, and then let it go. I’ll be ready to take advantage of the opportunity. Keep out of sight yourself, and tip off our young friend at the desk, so that she’ll know what to do when Stone complains. Tell her to keep the whole affair quiet. I’ll let you know in due time how I’ve succeeded; and if I need any more help later on I’ll surely call upon you.” “I get you,” declared the house detective, and turned briskly away. Nick Carter quietly returned to his own room, locked himself in, and went to his window. Stone’s light was still burning, but Crawford’s window was as dark as before. To all appearances, Stone was biding his time as Follansbee had advised. The detective consulted his watch once more, made a few preparations, and then, stationing himself finally at his open, unlighted window, awaited the prearranged signal. At the end of ten minutes a startling din came to his ears from near at hand, and he prepared for action. The time had come. CHAPTER XXIII. THE HYPODERMIC. The detective’s scheme was simplicity itself, and it promised success. He had merely instructed Stickney to have Stone’s bell rung at the appointed time, and to keep it ringing continuously until the miner should leave his room in desperation to complain of the nuisance. If it worked out as Nick hoped, Stone’s absence would give him the opportunity he sought, and meanwhile the miner would be informed that the electrical apparatus must have been deranged in some way. It would be looked to and “remedied;” whereupon, the ringing would cease, and Stone would receive the apologies of the management.