The Riddle of the Sands;

The Riddle of the Sands: A Record of Secret Service enjoyed immense popularity in the years before World War I. It is an early example of the espionage novel and was extremely influential in the genre of spy fiction. It has been made into both a film and TV film. Carruthers, a minor official in the Foreign Office, is contacted by an acquaintance, Davies, asking him to join in a yachting holiday in the Baltic Sea. Carruthers agrees, as his other plans for a holiday have fallen through. He arrives to find that Davies has a small sailing boat (the vessel was named Dulcibella, a reference to Childers's own sister of that name), not the comfortable crewed yacht that he expected. Davies gradually reveals that he suspects that the Germans are undertaking something sinister in the German Frisian islands, based on his belief that he was nearly wrecked by a German yacht luring him into a shoal in rough weather. Carruthers and Davies sail back to the Frisian Islands and spend some time exploring the shallow tidal waters of the area, moving closer to the mysterious site where there is a rumoured secret treasure recovery project in progress.