"Hardy Boys (Fictitious characters) Juvenile fiction." . . "Mystery and detective stories." . . "Teenage boy detectives Fiction." . . "Boy detectives Fiction." . . "Treasure troves Juvenile fiction." . . "Mystery fiction." . . "Detective and mystery stories." . . . . "Treasure troves." . . . . . . . "The secret of Pirate's Hill"@en . . . . . . . . . "Fiction" . "Fiction"@en . . . . . "Electronic books"@en . . "Detective and mystery stories"@en . "Detective and mystery stories" . . . . "In a series of hair-raising adventures both on land and undersea, the teenage brother detectives pit their wits against some of the most ruthless criminals they have ever encountered."@en . . . . . . "The secret of pirates' hill" . "The secret of pirates' hill"@en . . . . . . . . . "Juvenile works"@en . "Juvenile works" . . . . . . . "The secret of pirates- hill" . . . . . . . . . "The SECRET OF PIRATES' HILL" . . . . "The secret of Pirates' Hill"@en . "The secret of Pirates' Hill" . "Hired to locate an old Spanish cannon, the Hardy brothers uncover an even greater treasure after perilous underwater adventures."@en . "Hired to locate an old Spanish cannon, the Hardy brothers uncover an even greater treasure after perilous underwater adventures." . . . "The Secret of Pirates' Hill #36"@en . "Detective and mystery stories Juvenile fiction." . .