The prologue introduces Katharina, who receives a phone call on her birthday of her former lover's death. Katharina is in Pittsburgh where she lights a candle and plays music in memory of Hans. Upon returning to Berlin, she finds boxes of Hans's belongings, which include letters, photographs, and personal items that trigger memories of their relationship from 1986 to 1992.
Katharina and Hans meet on a bus in East Berlin. Katharina is a nineteen-year-old apprentice typesetter, and Hans is a married writer in his fifties. They quickly become attracted to each other despite their age difference and marital status. Their initial conversation leads to coffee and the beginning of a complex yet passionate affair. It quickly develops through secret meetings. Katharina's youth captivates Hans, which contrasts with his stagnant marriage. Their affair becomes intense, with loving encounters and intellectual conversations.
The political climate of East Germany poses challenges for them as they navigate the restrictions on personal freedoms. However, they find solace in their clandestine meetings and share a love for literature and music. Their relationship grows stronger despite these difficulties.
As their affair deepens, Hans feels increasingly conflicted about his double life. His wife remains unaware of the affair, but the strain on Hans is apparent. Meanwhile, Katharina struggles with being the other woman and yearns for public acknowledgment of their relationship. Hans's career as a writer and his political affiliations begin to affect their relationship. The pressures of maintaining it mixed with the fear of discovery increase. Katharina becomes more involved in Hans's world, meeting his friends and colleagues.
In Frankfurt, Katharina cheats on Hans with Vadim while working late into the night on a new production. Consequently, Hans reproaches Katharina for the infidelity and declares their relationship over as he accuses her of destroying their bond. The devastated Katharina writes her responses, grappling with the possibility of losing Hans forever.
During a trip to Dresden with her father, Katharina tries to explain her deep connection to Hans, but her father dismisses monogamy as merely societal. She feels a strong emotional resonance with a sculpture depicting a contradictory figure.
In Berlin, their meetings become emotionally conflicting as Katharina faces solitude each time she returns home. They walk around the city, avoiding places that remind them of happier times to preserve those memories. Despite trying to move forward, the weight of Katharina’s betrayal and Hans’s bitterness hangs over them. They continue to navigate their fractured relationship, marked by Hans's reproachful recordings and Katharina's efforts to reconcile her actions with their shared past. Katharina shares discussions with Rosa that prompts her to question her relationships. Meanwhile, Hans navigates political changes in East Germany.
Later, she reflects on her recent trip to Venice and her return to Berlin. She muses on the changing dynamics of the city and the reunification of Germany. Katharina's observations of the evolving consumer culture and the disparities between East and West highlight the uncertainties of the post-reunification period. In this final passage, Katharina delves into the files of an informal collaborator known as Galileo. As she sifts through the documents, she contemplates the dualities of human existence and the disillusionment. She walks through the streets of Berlin while grappling with her past and the uncertainties of the future.
