THE unstoppable Donald E. Keyhoe had a story in a majority of the issue of Flying Aces from his first in January 1930 until he returned to the Navy in 1942. Starting in August 1931, they were stories featuring the weird World War I stories of Philip Strange. But in November 1936, he began alternating these with sometime equally weird present day tales of espionage Ace Richard Knight—code name Agent Q. After an accident in the Great War, Knight developed the uncanny ability to see in the dark. Aided by his skirt-chasing partner Larry Doyle, Knights adventures ranged from your basic between the wars espionage to lost valley civilizations and dinosaurs. Still in Spain, Richard Knight heads back into war-torn Spain in an effort to retrieve the Green Madonna—only to find The Hawk has kidnapped Benita Navarre!

Through those blood-red skies that hung like the hand of Doom over war-wracked Spain, there swooped a winged, incarnate devil—a greedy ghoul men called “The Hawk.” Sparing neither Rebel nor Loyalist, this eerie fiend struck without warning. Wretched Iberia herself was his victim; ruthlessly he pounced upon her, and from her defenseless form his merciless talons tore priceless treasures. And now those bony claws clutched the gleaming “Green Madonna”—sought to wrench from that brilliant jewel a secret known only to Death.

• Download “Wings of the Emerald” (September 1937, Flying Aces)