In the days leading up to World War II, Katie O'Hara (Ginger Rogers), an American burlesque performer masquerading as American socialite "Katherine Butt-Smith", pronounced byüt-smith, is about to marry Austrian Baron Von Luber (Walter Slezak). Foreign correspondent Pat O'Toole (Cary Grant) suspects Von Luber of being a Nazi sympathizer and tries unsuccessfully to get information from Katie by deceit, but is warned off by Von Luber.