"If _he_ knew who's leased The Cedars," murmured Alden, "he'd be a sergeant sooner than he expects." Which remark was the last contributed by any of the party for some considerable time. Alden's description of the road before The Cedars as a lonely one was fully justified. From the time of Martin's return until that when the big car drove up and turned into the drive, not a solitary pedestrian passed their hiding-place. A laggard moon sailed out from a cloud-bank and painted the road white as far as the eye could follow it. Then came a breeze from the river, to sing drearily through the trees. In the intervals, when the breeze was still, its absence seemed in some way, to stimulate the watchers' power of hearing, so that they could detect vague sounds which proceeded from the river. The creak of oars told of a late rower on the stream--a voice was wafted up to them, to be drowned in the sighing of the leaves set swaying by the new breeze. Then came the car. The whirr of the motor announced its coming from afar off; but, so swiftly did it travel, that it was upon them a moment later. As it swung around and on to the drive of The Cedars its number showed clearly. "3509," said Martin. "That's Mr. Antony Elschild!" "Gee!" said Oppner, and his sandy voice shook somewhat, perhaps owing to the chill of the breeze. "This is getting real exciting!" The car was delayed some little time before the door of the house, then driven around, and out at the further gate of the drive. It returned by the way it had come, racing down the hill at something considerably exceeding the legal speed. The _thud-thud-thud_ of the motor died away, and became inaudible. "I'm glad the police aren't with us, and yet sorry," said Oppner. "This is a whole-hog conspiracy properly. No wonder he was so hard to catch; look at the class of people he's got in with him! Think of Elschild! Gee! There's goin' to be a scene in a minute." "For the present," said Alden, "we'll make no move; we'll just sit tight. There's maybe a lot to arrive yet." Just before the breeze came creeping up from the river again, _thud-thud-thud_ was borne to their ears. Another car was approaching. CHAPTER XVI THE LAMP AND THE MASK "10761," said Alden. "I wonder whose car that is." None of the watchful trio had any idea. But whomever was within it, the second car performed exactly the same man[oe]uvres as the first, and, a few moments after its appearance, was lost to sight and hearing once more. But a matter of seconds later, came the familiar _thud-thud-thud_; and a third car plunged up the hill and went swinging around the drive. Again, no one of the three was able to recognise the number. Out by the further gate of the drive it passed, turned, and flashed by them in the darkness, to go leaping down the slope. "Three," said Alden. "I wonder if there's any more." His tone was thoughtful. "Say," began Mr. Oppner, "we'd better get on with it now, because----"