The Numbered Account — Ann Bridge

Julia Probyn, like most people, knew very little about anonymous numbered accounts in Swiss Banks. Until her cousin, Colin Munro, asked her to look into the matter of one containing a fortune, for his fiancée Aglaia Armitage, left to her by her Greek grandfather. Then Julia learned a great deal.

But besides bonds and debentures, old Mr. Thalassides, proved to have left documents of vital interest to the British Secret Service, and to other Powers as well, in the vault with them. When these disappear, the hunt begins…