Lili Smith (Andrews) is a popular British music hall singer who is regarded as a femme fatale and has been known to throw a bit of striptease into her act. However, Lili has a secret: she's actually a German spy, and the uncle she dotes upon is really Von Ruger (Jeremy Kemp), a fellow espionage agent and her contact for the Huns. In hopes of gaining valuable information, Lili begins using her feminine wiles on Maj. William Larrabee (Rock Hudson), a top American pilot. However, Lili soon discovers that she's falling in love with Larrabee and can't find the courage to betray him; Larrabee discovers Lili's secret, but he refuses to turn her in.
