Before leaving on grant to Cold War Berlin, Professor Renate Seiler discovers letters among her late mother's effects that point to her deceased father Kurt's Nazi ties. Renate decides to investigate. En route in Germany, she visits her Aunt Hildegard, who says Herr Westerheim, an old friend from Berlin, might know more. Unable to reach him, Renate seeks diversion and goes with Robert Bennett to hear Christine, a chanteuse at the Black Panther. When Renate returns to the club on her own, Christine asks for her phone number. At a local eatery, Renate falls into a casual conversation with Alfred and Heinz, and offers to deliver medicine to their sick friend in East Berlin. At the contact apartment she meets Dieter. On their way to the train station, Dieter invites Renate to the Cafe Budapest after scheduled eye surgery. Over coffee, Robert tells Renate that Christine is a lesbian. Renate visits Westerheim at his home where she learns the family secret: Renate's father spied for the Nazis to protect her mother - who was half-Jewish - leaving Renate further shaken over her father's actions and her newly discovered ethnic heritage. Christine woos Renate to her place for an evening, and seduces her. At home, Renate mulls over her emotional and sexual confusion. When Renate meets Dieter in East Berlin, she feels an instant rapport. He invites her to come over to East Berlin the next week. Over dinner, Dieter asks Renate to help him escape to West Berlin. Plagued by guilt about her father, and swayed by Dieter's plight, Renate agrees. Heinz picks up Renate for a trial drive in a VW weighted down to equal Dieter' tall frame. While the car is being rebuilt, Heinz's colleague John Baker takes Renate on a test drive past the contact location in East Berlin where she will pick up Dieter. After several dates, Renate stays over the weekend with Christine. On Dec. 23, she waits for mechanics to hide Dieter in the VW. On the way back to West Berlin, the tire blows. As she struggles with the valve, a man in a Western car stops to help. At the border, she guns the motor and shots ring out. A bullet penetrates her arm; she blacks out, and awakens in a hospital bandaged around her chest, head and arm. Christine locates Renate's hospital room. Later, Dieter arrives and introduces his fiancee Karin. They are heading to West Germany for further treatment on Dieter's eyes. Renate is crushed. Before the hospital releases Renate to Christine's care, two American CIA agents question her about the escape. Over time, the relationship between Christine and Renate deepens. When Renate's cast is removed, Christine introduces her to lesbian life in Berlin at a dive called Les Biens. Renate reconnects with Robert at the Free University faculty lounge - and Frank joins them. The two US agents phone contact Renate. They want her to work for them, and will supply details in the States. Renate stops for a drink at the LB and chances upon Greta and Ulli from the Panther. The two talk about their difficult lesbian lives in Berlin. Christine's gets a solo evening at the club. Renate drops everything to manage the event. While Christine visits her ailing mother Irena, Renate sees Westerheim again. In a city park, Westerheim tells Renate about his involvement in the Nazi VI rocket, and his work on the Atom bomb for the US military. He has retired and is emigrating to Australia. The bond between Renate and Chris strengthens when Renate meets Irena and Chris visits Aunt Hildegard. At home, endless discussions follow as the date for Renate's flight looms ahead. Chris begs Renate to stay, but there is no choice but to resume her teaching post in the US and leave Chris behind. At the airport the atmosphere is drenched in hopelessness and sadness. During Renate's flight to Frankfurt, Eva Steinberg, a graduate student in German at the University of Wisconsin, strikes up a conversation. Eva will be on the same plane from Frankfurt to New"