- "When you go up against crime, there's always someone ready to shoot you down...."
- — Tagline, from the front cover
Sky High is the 113th book in the The Hardy Boys Casefiles series.
Chet has won a ticket to ride from the International Ballooning Club, and the Hardys have learned that it could also be a ticket to disaster. A series of suspicious accidents have plagued the show, and with the upcoming Lift Challenge offering a $100,000 prize, the organizers of the event have received an anonymous threat: "Pay up or die!"
Frank and Joe recognize the gravity of the situation. What goes up must come down. But will anyone get hurt when the fall comes? The boys launch a high-stakes, high-risk investigation in search of the extortionist, knowing that the warning is more than hot air. At these heights, a tiny flame could turn one of the balloons into a ball of fire!