The Phantom Spy — Max Brand

Lady Cecil was lovely, headstrong, and attached to the British Secret Service. Willie Gloster was a rich American playboy with a taste of danger. Together -- and at great peril -- they had recovered stolen military plans. Their loss might have meant England's ruin.

But the precious papers disappeared again, and only one man -- the phantom spy -- could help Lady Cecil retrieve them. Then Lady Cecil herself vanished. And Willie Gloster set out on a daring one-man rescue mission into the savage jungle of international intrigue to find the beautiful woman he loved, and to solve the strange mystery of the elusive spy whose face nobody knew!