"Hardy Boys (Fictitious characters)" . . "Mystery and detective stories." . . "Teenage boy detectives Fiction." . . "Boy detectives Juvenile fiction." . . "Teenage boy detectives Juvenile fiction." . . "Brothers Fiction." . . "Detective and mystery stories." . . "Detective and mystery stories Juvenile fiction." . . "Hardy Boys (Fictitious characters) Juvenile fiction." . . "Boy detectives Fiction." . . "Hardy Boys (Fictitious characters) Fiction." . . "Sheriffs Fiction." . . . . . . . . . "The Secret Warning" . . . . "The Secret Warning #17"@en . "When a ship supposedly carrying a gold Pharaoh's head sinks, Joe and Frank help their father discover whether the owner is trying to defraud the insurance company and along the way encounter a ghostly apparition and a scuba diver with a grudge."@en . . . "Electronic books"@en . . . . "Secret Warning"@en . . . . . "Hardy-Guttene og dykkermysteriet" . . . "A mystery involving the golden head of a pharoh leads the boys into a dangerous island adventure."@en . "Frank and Joe investigate the legend of Whalebone Island when they receive a warning concerning a sunken freighter" . "Juvenile works" . "Juvenile works"@en . . . "Mystery fiction"@en . . "The secret warning" . "The secret warning"@en . . . . . . . "Strange events involve Frank and Joe Hardy in a mystery which shrouds an ancient treasure -- the golden head of the Pharaoh Rhamaton IV. First, a cryptic unsigned warning from Egypt; second, the ghost of a bloodthirsty pirate of the eighteenth century, who, according to legend, haunted nearby Whalebone Island years ago and recently has reappeared. The owner of the million-dollar golden Pharaoh's head claims it was aboard the freighter Katawa, which sank not far from Whalebone Island. But suspicious developments indicate that Mehmet Zufar may be trying to defraud the shipping line's insurance company. Frank and Joe enthusiastically accept the challenge of their famous detective father to assist him in investigating the complex case for Transmarine Underwriters. A puzzling clue leads the Hardys to Whalebone Island, where they almost lose their lives in a violent explosion. Someone desperately wants to get rid of them. But who? Is it the ghostly pirate? Frank and Joe's perilous scuba-diving search in the ocean depths off the island yields electrifying discoveries that cap the climax of this exciting mystery. - Flyleaf."@en . . . . . . "The SECRET WARNING" . . . . . . . "Frank and Joe investigate the legend of Whalebone Island when they recieve a warning concerning a sunken freighter."@en . . . . . "False robbery charges, Joe's disappearance and other strange things occur when Frank and Joe set out to retrieve their father's important papers from a diver."@en . . . "The Secret warning"@en . . . . . "Detective and mystery stories"@en . . . . . . . "Strange events involve Frank and Joe Hardy in a mystery which shrouds an ancient treasure, the golden head of the Pharaoh Rhamaton IV."@en . . . . "Frank and Joe investigate the legend of Whalebone Island when they receive a warning concerning a sunken freighter."@en . . . "Fiction" . "Fiction"@en . . "Mystery fiction." . .