"Airplane Boys Discover the Secrets of Cuzco" by E. J. Craine is an adventure novel written in the early 20th century. The story features young protagonists Bob Caldwell and Jim Austin, who are part of the "Flying Buddies," as they navigate a series of thrilling escapades involving flying, mystery, and rivalry. The narrative is set against the backdrop of their lives on a ranch, blending elements of aviation with youthful camaraderie and the pursuit of adventure. At the start of the story, Bob Caldwell experiences a harrowing incident when his beloved plane, Her Highness, catches fire during a flight, forcing him to parachute to safety. As he grapples with the loss of his aircraft, he and his step-brother, Jim, engage in discussions about the circumstances surrounding the fire, suspecting foul play. The boys' investigation leads them to renewed excitement when they anticipate the arrival of a new plane. Soon, they find themselves embroiled in a mystery involving Carl Summers, a young deputy, and the elusive young outlaw Arthur Gordon, who has set the stage for further adventures. Their journey takes them through atmospheric challenges, danger, and the thrill of discovery, underlining themes of bravery and friendship among the young aviators. (This is an automatically generated summary.)