Two aviator-detectives, Jack Ralston and his companion Perk, undertake a government assignment that propels them from a hotel fire into a cross-country aerial pursuit. Their journey moves from flying-field departures and mechanical troubles to treacherous mountain trails and northern wilderness, bringing them into conflict with smugglers, fur traders and mounted police. They confront storms, headwinds, wildlife and damaged equipment, test survival skills around campfires, and execute a daring dead-stick landing before concluding the chase across the border.