Books in Hardy Boys Casefiles, No 23 series

The Hardy family's vacation in Hawaii is marred by attempted murder when their friend, champion surfer Jade Roberts, is hunted by the man her father helped bring to justice

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children

Competing in the Suntex Solar Challenge, a race across the Arizona with solar-powered cars that offers $100,000 to the winners, the boys encounter a ruthless terrorist who is determined to win at any cost. Original.

The Hardy brothers, Frank and Joe, are back for further adventures in this story.

Callie Shaw brings the Hardy boys a top-secret code book she has accidentally acquired and the three become targets for the book's owner, who will do anything to get it back.

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Summoned to northern Arizona by their father's friend, Sam Gentle, Frank and Joe Hardy arrive to find Sam murdered, a death that they suspect was caused by Sam's research at Titan Chemical Industries. Original.

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When the sister of their friend Ben Martin, a recent lottery winner, is kidnapped, Frank and Joe Hardy find numerous shady suspects as they try to rescue Ben's sister before tragedy strikes. Original.

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While in London, Joe and Frank Hardy begin an investigation into the disappearance of beautiful English actress Jill Seabright, a case that could have them end up in a rat-infested dungeon