“That’s all right,” said Laura, in response to the girls’ gibes. “I’ll get in some clever work, with nothing but a silly old photograph album as a clue, or a motive—oh, well, I don’t know just what the album is yet, but an album is worse than commonplace, it is plumb foolish as a center around which to work. Oh, ho! Great Lady Detective! Solves most marvelous and intricate mystery with only the slightest of clues, an old photograph album, to point the way! Oh, ho!” The girls could never have told exactly why, but they kept the mystery of the album and Miss Arbuckle’s strange actions to themselves, with one exception. They did confide their secret to fluffy-haired, blue-eyed Connie Danvers. For they had long ago adopted Connie as one of themselves and were beginning to feel that they had known her all their lives. Connie had been interested enough in their story to satisfy even the chums and had urged Billie to describe the pretty children in the album over whom Miss Arbuckle had cried. Billie tried, but, having seen the pictures but once, it was hardly to be expected that she would be able to give the girls a very clear description of them. It was good enough to satisfy Connie, however, who, in her enthusiasm, went so far as to suggest that they form a Detective Club. This the girls might have done if it had not been for an interruption in the form of Chet Bradley, Teddy Jordon and their chum, Ferd Stowing. The boys had entered Boxton Military Academy at the time the girls had entered Three Towers Hall, and the boys were as enthusiastic about their academy as the girls were about their beloved school. The head of Boxton Military Academy was Captain Shelling, a splendid example of army officer whom all the students loved and admired. They did not know it, but there was not one of the boys in the school who did not hope that some day he might be like Captain Shelling. Now, as the spring term was drawing to a close, there were great preparations being made at the Academy for the annual parade of cadets. The girls knew that visitors were allowed, and they were beginning to wonder a little uneasily whether they were to be invited or not when one afternoon the boys turned up and settled the