6A blind peddler's warning and a weird glass eye plunge Frank and Joe Hardy into one of the most baffling cases they have ever tackled. The young detectives' investigation takes them to a walled estate guarded by savage dogs, where a wealthy businessman is hiding out in fear for his life. In a climax that will hold the reader spellbound with suspense, Frank and Joe find themselves trapped in a sinister house of mystery where there seems to be no escape!