Carroll sensed that there was a reason for her stopping in the middle of her sentence and, looking around, found the pussy-footed head waiter beside him, apparently waiting for a call. Silently damning the custom that made it obligatory for waiters to move without making a sound, Carroll wandered off across the lobby, determined to take a stroll around the block before settling down to his night's vigil. A stop at the information desk, however, rewarded him with the news that Lord Wimbledon was giving a dinner in his apartments the following evening to the British ambassador--that being all the hotel knew officially about his Grace's movements. "I'll take care to have half a dozen extra men on the job," Carroll assured himself, "for that's undoubtedly the time they would pick if they could get away with it. A single bomb then would do a pretty bit of damage." The evening brought no further developments, but shortly after midnight he determined to call the Rennoc, in the hope that the pretty telephone girl was still on duty and that she might finish telling him what she knew of Conner's. "Hotel Rennoc," came a voice which he recognized instantly. "This is Dave Carroll speaking," said the operative. "Can you tell me now what it was you started to say about Conner's?" "Not now," came the whispered reply. Then, in a louder voice, "Just a moment, please, and I'll see if he's registered." During the pause which followed Dave realized that the girl must be aware that she was watched by some one. Was it the silent-moving head waiter? "No, he hasn't arrived yet," was the next phrase that came over the wires, clearly and distinctly, followed by instructions, couched in a much lower tone, "Meet me, Drive entrance, one-five sure," and then a click as the plug was withdrawn. It was precisely five minutes past one when Carroll paused in front of the Riverside Drive doorway to the Rennoc, considering it the part of discretion to keep on the opposite side of the driveway. A moment later a woman, alone, left the hotel, glanced around quickly, and then crossed to where he was standing. "Follow me up the street," she directed in an undertone as she passed. "Michel has been watching like a hawk." Dave knew that Michel was the head waiter, and out of the corner of his eye he saw a shadow slip out of another of the hotel doorways, farther down the Drive, and start toward them. But when he looked around a couple of blocks farther up the drive, there was no one behind them. "Why all the mystery?" he inquired, as he stepped alongside the girl.