Bored by the stifling routine of high-society London, a young Foreign Office official accepts a seemingly innocent invitation from an old acquaintance to go yachting in the Baltic Sea. But what begins as an uncomfortable escape from the city soon plunges him into a chilling web of international intrigue.

Aboard the cramped, scrubby little yacht Dulcibella, Carruthers discovers that his host, the eccentric and resourceful Davies, is hiding a dark secret from his solo voyage through the treacherous, sand-choked channels of the Frisian Islands. An encounter with a mysterious German and a sinister barge-yacht has left Davies deeply rattled-and convinced that something far more dangerous than foul weather is brewing off the coast.

The Riddle of the Sands is a masterful blend of gripping nautical adventure and taut suspense. As the two men navigate treacherous shoals, shifting tides, and violent autumn gales, they must also navigate the deadly secrets of a foreign power. Will they unravel the true purpose of the shifting sands before it's too late?