The four lads went camping, and it was hoped that Frank would forget his troubles, but, instead, he seemed to get right into the thick of them. Frank, for some years, had believed his father dead, but it transpired that he was not. Mr. Roscoe was kept in a private insane asylum, though he had full possession of his reason, only he was made ill by drugs constantly administered to him by men who had an interest in keeping him out of the way. How he was rescued, and the perils the boys ran in saving him after they had released him from the institution, you will find set down in the third book.