Sky King

During a fierce thunderstorm, Sky picks up a mayday call from a Air Force courier plane which is about to run out of gas. The Air Force request Sky's assistance in locating the downed aircraft because the pilot is transporting secret documents that are of interest to foreign governments. Sky locates the plane wreck, but the pilot is nowhere to be found. When he discovers that the navigational instruments have been tampered with, Sky fears that enemy agents may have located and stolen the secret plans and are headed for the nearby Mexican border.

When Penny discovers a wounded carrier pigeon carrying a valuable ruby attached to its leg, Sky suspects a gang of jewel smugglers is operating in the area. With the help of a Mexican police detective, Sky sets up to break up the criminal operation.

A crooked express agent fakes a hold-up to steal gold from his company's vault. He uses an old stagecoach to get the stolen loot out of town.

While helping a friend run his freight airline after an accident, Sky stumbles across a gold-smuggling operation.

Sky's efforts to prove corruption in the county clerk's office nearly result in disaster, when Sky's foreman, a non-pilot, must land the Songbird when Clipper becomes too ill to fly the plane.

Sky becomes suspicious when a Eastern woman shows up in Grover claiming to be the long-lost niece and heir of a dead rancher.