Charles Hickman

Derwent dreams up an unbreakable alibi for a murder. Once the crime is attempted, it then falls to Pember and Brace of Scotland Yard to sort things out.

Inspector Steve Trent tracks the stolen Cortez emerald, last pilfered by a murdered gangster.

This early docudrama uses dramatic reenactment, working models of early flying machines, and archival footage to trace man's attempts to fly from ancient times through the 1930s.