The sky became overcast, so there was little light. The black shadow of the shore seemed potent with dangers. Bart had his second watch on deck, and it was not far from midnight when he was startled to hear a voice hailing from the shore: "Ahoy, the yacht!" "What do you want?" asked Bart, gripping a revolver and staring toward the point from which the voice had seemed to come. "Who are you?" "Caleb Cooler, at your service," came back the answer. "I thought I'd tell you something that may relieve your minds somewhat. Frank Merriwell is alive and unharmed." Bart gasped. "Why do you come to tell us that?" he asked. "Because I know you are worrying about him. Don't worry. He will be with you to-morrow." This angered Bart so that he lifted his revolver, being tempted to send a random shot toward the point from which the voice seemed to come, but he changed his mind and lowered the weapon. "So long," called the voice of the queer old man. "Turn in and sleep. You won't be troubled." "That is what they want us to do," thought Bart. "It is a trick. But they can't fool us that way." No further sound was heard from the shore. Cooler did not answer, although Bart called to him several times. Jack had heard Hodge speaking, and he came on deck. When Bart told Diamond what had happened, the latter was furious. "If I had been here, I would have fired six shots in his direction," he declared. Diamond took his turn on deck, and it was about two o'clock when he fancied he heard the sound of oars. The sound came nearer and nearer, till at last it seemed that the boat reached the island, and then the sound was heard no more. Morning dawned, and Browning arose in a strangely agitated state of mind. Never had his companions seen him in such a condition. When asked about it, he said: "Boys, I had a queer dream. I'm going to tell you what it was. I dreamed that Frank Merriwell is buried in the grave on the island. I thought him buried alive. We dug him out and restored him to life." "It can't be that Merry is buried there, for the mound has not been disturbed lately," said Diamond. "All the same," declared Browning, "I am going to open that grave. I am going to know the secret it holds." CHAPTER XXIX. THE SECRET OF THE GRAVE. Browning was determined, and it was not long before he had worked the others into a state of excitement over it. Without waiting for breakfast, they sprang into the boat and rowed ashore. "I saw some tools in the sheds at the end of the railroad," said Bruce. "We will secure them." The path was taken, and they passed through the old quarry and down the track to the sheds. There they found a pick and spade. With those in their possession, they hastened to the black glade in which lay the grave. For once in his life Bruce Browning was filled with energy--he was aroused. But even as he reached the grave, he halted suddenly, his hand uplifted, hoarsely gasping: "Listen!" The boys were silent. "Help!"