It took the trio nearly half an hour to reach the summit, but when they gained the top of the “camel’s back” they were in a fine position for observation. Not far below them was the placid water of the lagoon, and the black hull of the _Hatteras_ was plainly discernible. Here, too, they solved the mystery of the _Firefly’s_ whereabouts. They had wondered where Flagg had hidden her. Now they could see her moored behind the wreck, in such a position that she would not be observed by any one entering the lagoon. “I wish I had brought my glasses,” Dave said. “You’d only have lost ’em in the scramble,” his companion commented. “Besides, we shall be able to see all we want in a few minutes. Those clouds are rolling away fast.” Half hidden behind a rock, the three peered down at the strange scene for some time. The rain had ceased altogether, and the sand glistened silvery in the moonlight. Suddenly Dave took a quick inward breath, and his fingers tightened on the rock he was leaning against. Stealthily, silently, three forms emerged from the shadow below, and moved in the direction of the _Nautilus_, which now lay awash, canting over slightly. Of the three forms it was easy to distinguish that of Joe Flagg. [Illustration: Three forms emerged and moved in the direction of the _Nautilus_] “What’s their game now?” Dave asked, speaking in a low voice, as though afraid of being heard by those beneath, even at that distance. “A little midnight exploration party of some sort,” Tempest replied. “We’ve got Flagg guessing, and he wants to be sure how things stand. He’s not getting much sleep, anyway, since we disturbed his operations. Look, they’re making a bee-line for our old tub, but what on earth they are after I cannot imagine, unless it is to make sure we are not on board.” “There isn’t much there for them to steal,” said the boy. Tempest laughed softly. “Flagg isn’t that sort of a thief, lad,” he observed. “It takes bigger things than what we have there to interest him. He is quite brainy, in a fashion. I guess they would tell us that in Dogtooth City, if we could ask them; but they haven’t got any pleasant memories of him, you may be dead sure. No siree! Joe Flagg is up to some scheme, and I’d give a lot to know what it is. He has the advantage over us for the moment, though. We can do nothing――except keep our eyes open.” Dave nodded. As a matter of fact it was all he could do to keep his eyes open, in spite of the mysterious manœuver that was going on under them. Warily Flagg approached the _Nautilus_, and while he stood on guard with the rifle his two Kanakas climbed over the side. “Good-by, binoculars!” muttered Dave.