In Bern, Switzerland, as Raimund Gregorius (Jeremy Irons) strolls across a bridge en route to his university, he spots a young woman donned in a striking red coat precariously perched on the railing, seemingly poised to jump. Without a moment’s hesitation, he abandons his briefcase and rushes to save her, managing to pull her to safety. In an unexpected turn of events, she helps him retrieve the scattered papers from his briefcase and accompanies him to his class. However, instead of remaining to converse, she mysteriously departs in the midst of his lecture, leaving her coat behind.
Perplexed and worried, Raimund retrieves her coat and desperately searches for her, but she has vanished. Upon inspecting her coat, he discovers a small book—a memoir by Amadeu do Prado. Stamped with the address of a bookstore, he decides to investigate further and heads there. The bookseller recalls the girl purchasing this rare book, and as Raimund flips through its pages, a train ticket to Lisbon drops out. Realizing the train is departing in just 15 minutes, he contemplates his next move, ultimately deciding to embark on the journey himself, all the while delving into the intriguing contents of the book.
As he reads, he learns about Amadeu do Prado’s life in Lisbon and sets off on a quest to find him, hoping that uncovering Amadeu's story will lead him back to the mysterious woman. Upon arrival, he visits Amadeu's residence, where he is greeted by Adriana (Charlotte Rampling), the writer’s sister, who creates an atmosphere of intrigue, suggesting her brother is still alive. During his visit, Raimund learns that Amadeu was a doctor, and only a limited number of copies of his memoir were published. When curious about their father's fate, Adriana’s hostile response raises more questions than it answers. As he leaves, a maid alerts him that Amadeu can be found at the local cemetery, where he discovers the writer's grave—Amadeu had passed away in 1974.
As the tale unfolds, Raimund's journey takes another turn when he’s accidentally struck by a bicycle, resulting in damaged glasses. While getting a new pair from a local optician, Mariana (Martina Gedeck) becomes intrigued by his story and reveals that her uncle knew Amadeu personally and would like to meet him. Together, they visit Mariana's uncle, João Eça (Tom Courtenay), who shares gripping memories of their time in the resistance against the oppressive Salazar dictatorship, with the narrative exploring flashbacks of their shared struggles and sacrifices.
Moreover, Father Bartolomeu (Christopher Lee) also provides recollections of Amadeu’s early years, detailing how he formed a close bond with Jorge O'Kelly ([August Diehl]), a boy from a modest background. Their friendship thrived amidst the oppressive atmosphere, fueled by a mutual passion for knowledge considered dangerous under Salazar’s regime. In a pivotal moment, Amadeu delivers a graduation speech that openly critiques the dictatorship, infuriating his father, a respected judge.
Throughout his investigation, Raimund gathers insights into Amadeu's unexpected decisions and his profound impact on those around him. A significant revelation comes when João mentions that Amadeu saved the life of Rui Luís Mendes, known infamously as “the Butcher of Lisbon,” a fact that leaves his comrades appalled. It is then that Amadeu, seeking redemption and purpose, commits to join the resistance himself, eventually meeting Estefânia (Mélanie Laurent), a charming young woman who aids their cause but stirs deeper feelings in both men.
As the revolution brews, Amadeu’s sacrifices intensify; he heroically aids Estefânia's escape to safety in Spain. Driven by a desire to learn of Amadeu’s beloved, Raimund embarks on a journey to find the older Estefânia ([Lena Olin]) in her new life. Through their encounter, she communicates the significance of her past romance with Amadeu, deepening Raimund's understanding of the emotional tapestry that binds these characters.
Eventually, Raimund encounters the woman from the bridge once more in Lisbon. She confesses her despair upon discovering that her grandfather was, in fact, the notorious Butcher of Lisbon; yet, she is learning to find peace with her heritage. This series of events profoundly influences Raimund, leading him to re-evaluate his own life and priorities. As he prepares to return to teaching, he shares a moment with Mariana at the train station, where she suggests he consider staying behind. This tender encounter hints at new beginnings in his life, a gentle resolution to his tumultuous journey.
