Cyril Mansfield, a handsome young Englishman, is associated with the German Secret Service as a spy in England but is loyal to British intelligence, of which he is a member. He is loved by Lois, an American whose favor is sought by Rizzio, also a double agent, who suspects Cyril's disloyalty to Germany. With the intention of conveying false information to the Imperial German Government, Cyril, accompanied by his faithful mechanic, Handy, and by Lois, escapes to Germany, though Lois is herself abducted by Rizzio and brought to headquarters in a U-boat. Innocently, she betrays Cyril, and they are both sentenced to death. On a pretense of aiding Cyril, Rizzio urges Lois to accompany him on a diplomatic mission, but Cyril and Handy overcome their captors; and Lois and Cyril escape to England in his aircraft.