A simple invitation to join his friend Davies on a yachting expedition in the Baltic is the beginning of an extraordinary and dangerous adventure for the bored and worldly but clever Carruthers. As the two of them navigate the waters and treacherous, shifting sands of the Frisian Islands on board the Dulcibella, it is soon clear to Carruthers that Davies has more on his mind than a little duck shooting. As they encounter danger at every turn, Carruthers warms to his courageous and brave-hearted friend and through him begins to discover new strengths within himself and a sense of moral purpose. Sounding a warning of the dangers of a German invasion of Britain across the North Sea, Childers's gripping tale of espionage received immediate critical acclaim when it was published in 1903 and today retains its preeminent place in the genre.