A close-knit group of young friends take up the emerging art of aviation, acquiring and learning to pilot biplanes and a hydro-aeroplane. Their training produces daring solo flights, a long-distance race, and preparations for a public aero meet, while an aged aviator and a recovered black box introduce mysteries that lead to searches and rescues. Rivalries and jealous opponents prompt theft and sabotage, and a violent thunderstorm forces urgent skill and bravery in midair. The episodic narrative mixes practical flying lessons with competitive events and several adventurous setpieces that culminate at the final aerial meeting, where the principal dangers and puzzles are resolved.