"Not a sign," replied Simpson. "Just our luck. I suppose they'll do something as soon as it gets dark, and we'll be out of it." "May not," rejoined Atherton. "Anyway, if anything exciting does occur we'll rouse you up right enough." With that the "Wolves" reluctantly betook themselves off, and the "Otters" carried on the task of watching the mysterious yacht. The Scouts knew their work well. Even in the gathering twilight they refrained from showing themselves against the skyline. Each lad, with a cluster of gorse in his hat to still lessen the risk of detection, kept well behind cover. Night fell. There was no moon, but the stars gave sufficient light to distinguish the outlines of the coast and the grimly silent yacht, that, two hundred feet below, rocked gently on the bosom of the ocean. "It's eleven o'clock and slack tide," said Phillips to his Leader. "What do you say to this: suppose we get the others to lower us down the cliffs by the Tea Caves? It's hardly any distance." "What then?" asked Atherton. "Well, there being no tide, we could easily swim off to that yacht. It would be worth doing to find out what those fellows are doing on board." "I'm game," agreed Atherton. "But we'll have to mention it to Mr Buckley." "Do you think he'll let us go?" asked Phillips, anxiously. "If he won't there's an end to it," rejoined Atherton, sturdily. "So here goes, I'll ask." "A hundred yards from the shore at least," observed the Scoutmaster, when Atherton made the proposal. "Are you quite sure you can do the distance there and back?" "Both Phillips and I hold half-mile certificates, sir," said the Leader. "If the other fellows will lower us on to the ledge leading to the Caves, it will be a fairly simple matter to swarm down the rope to the base of the cliff." "Very well, then," assented the Scoutmaster. "But, whatever you do, exercise the greatest caution. Everest and Baker can remain here, the rest of the available 'Otters' can support you." "Thank you, sir," replied Atherton, saluting, and without further delay the work of preparation began. Green and Mayne were to remain on the top of the cliff above the ledge leading to the Tea Caves, the Scoutmaster was to descend to the ledge, make sure that there was no one lurking at the entrance to the caverns, and to assist the two swimmers during their descent and ascent to and from the sea. Noiselessly the little party gained the spot, almost opposite the anchored yacht. No signs of life were visible from the unlighted craft. Her outlines could only just be discerned against the dark surface of the water. It did not take the Scouts long to discover the holes into which the staves and crowbars had been driven on the first occasion of their first exploration of the Tea Caves. The tufts of earth that had been placed in them to hide the traces of the Scouts' operations were removed and two stout iron bars deftly inserted.