Riddle Of The Sands Part 1 Starring Michael York Jenny Agutter Simon MacCorkindale

Carruthers, an official in the British Foreign Office, is invited on a yachting holiday by his old friend Arthur Davies. Davies explains he has an agenda - while boating around the Frisian Islands he came across an old sailor, Dollman and his beautiful daughter Clara. He says he believes some men tried to kill him.

Carruthers and Davies discover the Germans are planning to invade Britain.