The Secret of Wildcat Swamp (The Hardy Boys, No. 31)

An invitation from Cap Bailey, science teacher at Bayport High, to accompany him out West to Wildcat Swamp on an archaeological expedition triggers off a series of dangerous events for Frank and Joe Hardy. On their way West the boys and Cap have a near-fatal accident in a private plane which has been sabotaged. Though warned to leave the area, Frank, Joe, and Cap doggedly remain until they have caught the cunning ex-convicts they are up against in this swift-paced adventure.

• The Crisscross Shadow (The Hardy Boys, No. 32)
• The Yellow Feather Mystery (Hardy Boys, Book 33)
• The Hooded Hawk Mystery (Hardy Boys, Book 34)
• The Wailing Siren Mystery (Hardy Boys, No. 30)
• The Clue in the Embers (Hardy Boys, Book 35)
• The Secret of the Lost Tunnel (Hardy Boys, Book 29)
• The Secret of Pirates' Hill (Hardy Boys, Book 36)
• The Sign of the Crooked Arrow (Hardy Boys, Book 28)
• The Ghost at Skeleton Rock (Hardy Boys, Book 37)
• The Secret of Skull Mountain (Hardy Boys, Book 27)