During the past few years the Rover boys had had numerous adventures, so many, in fact, that they can scarcely be hinted at here. While their father was in the heart of Africa, their Uncle Randolph had sent them off to Putnam Hall Academy. Here they had made many friends among the boys and also among some folks living in the vicinity, including Mrs. Stanhope and her daughter Dora, a girl who, according to Dick Rover's idea, was the sweetest creature in the whole world. They had also made some enemies, the worst of the number being Dan Baxter, a fellow who had been the bully of the school, but who was now a homeless wanderer on the face of the earth. Baxter came from a disreputable family, his father having at one time tried to swindle Mr. Rover out of a rich gold mine in the West. The elder Baxter was now in prison suffering the penalty for various crimes. A term at school had been followed by an exciting chase on the ocean, and then by a trip through the jungle of Africa, whence the Rover boys had gone to find their long-lost father. After this the boys made a trip West to establish their parent's claim to the gold mine just mentioned, and this was followed by a grand trip on the Great Lakes in which the boys suffered not a little at the hands of the Baxters. On an island on one of the lakes the Rover boys found a curious casket and this, on being opened, proved to contain some directions for locating a treasure secreted in the heart of the Adirondack Mountains. "We must locate that treasure," said Tom Rover, and off they started for the mountains, and did locate it at last, but not before Dan Baxter had done everything in his power to locate it ahead of them. When they finally outwitted their enemy, Dan Baxter had disappeared, and that was the last they had seen of him for some time. The Rover boys had expected to return to Putnam Hall and their studies immediately after the winter outing in the Adirondacks, but an unexpected happening at the institution of learning made them change their plans. Three pupils were taken down with scarlet fever, and rather than run the risk of having more taken sick, Captain Victor Putnam had closed up the Academy for the time being, and sent the pupils to their homes. "The boys will have to go to some other school," their Aunt Martha had said, but one and another had murmured at this, for they loved Captain Putnam too well to desert him so quickly. "Let us wait a few months," had been Dick's suggestion. "Let us study at home," had come from Sam. "Let us travel," Tom had put in. "Travel broadens the mind." He loved to be "on the go" all the time.