Two German spies and a woman physician (Suzy Kendall) are taken by submarine to Scotland where they enter the country at nightfall. Their mission is to assassinate the British Field Marshall Lord Kitchener. The woman's male companions are captured, but she escapes with the knowledge of what boat the Marshall is on. Boarding the submarine, the Germans make plans to bomb the boat with a series of strategically placed land mines. She travels from Russia to Germany to Britain and Spain as she double-crosses double agents in a cat-and-mouse game of espionage. A gruesome scene shows a German gas attack that peels off the flesh of the Allied soldiers as they writhe in agony. James Booth, Capucine, and Kenneth More also star in this World War I drama. ~ Dan Pavlides, Rovi