Fantastic Comics #21

The Black Fury springs into action when a freighter bound for Britain explodes at sea—and a survivor's account of an invisible saboteur points straight to the Fang, a ruthless operative working for foreign agents bent on crippling American weapons production. As the masked hero and his young partner Chuck track the elusive villain through the city, they're drawn into a deadly trap that threatens not only their lives but the fate of a crucial aircraft factory. The Black Fury must outmaneuver an enemy who can vanish without a trace before the Fang's final destructive blow lands.

Super-spy Yank Wilson, known as Q-4, boards a train crossing the Andes with a critical assignment: protecting the daughter of a South American president and ensuring a naval treaty reaches her father safely. When the villain Gruenhof and his Nazi-backed revolutionaries attempt to seize both the woman and the documents, Wilson must fight through gunfire and hand-to-hand combat aboard the moving train to complete his mission.