X or Igrek?. Christie A.

We present to your attention the book "X or Igrek?" Agatha Christie

Detectives-amateurs Tommy and Tappens solve almost the most difficult problem in their life. In the boarding coast of England, the old women, retired colonels and old virgins, lurked and prepared for active actions against England, live on the deserted coast of England. Conventionally they are called "X" and "Igrek". Who are they? How do they look? How to calculate them? The complex puzzle is supplemented by dangerous and unpredictable adventures...