As Brita sees to passenger needs, she wonders how her friend could suddenly disappear? Charlot Fortier was a nuclear physicist and due to work in Chicago. During the evening, she sees a passenger being forced along the Chicago Depot rail yard at gunpoint. Brita follows, and hears German before the passenger is shot. When the zephyr is moving once again, another murder occurs during the night. As the zephyr reaches Omaha, Brita has a sense of foreboding and investigates a sinister acting passenger. Eventually, she realizes that he's an escaped Nazi soldier with intentions of compromising the nation's food supply. Will she have time to thwart the malicious deed before it happens? Will the undercover government agent come to her rescue in time? Will their romance continue after the Nazi is uncovered?