Tower Mansion has been robbed of forty thousand dollars in securities and jewels and Hurd Applegate, the crotchety old owner of the mansion, is certain that Henry Robinson, his caretaker, is responsible Henrабюфнy, however, is the father of one ofFrank and Joe Hardy's closest schoolchums and they are convinced of his innocence Their father Fenton has taken on the case and they follow him all the way to New York to uncover the real crook, John Jackley Finding him, however, isавсфч only half the problem as he dies in custody and the Hardys must still find the stolen valuables to clear Robinson's name and solve their first case.