Berlin in 1995. Michael Berg watches an U-Bahn pass by—then flashing back to a tram in 1958 Neustadt. A 15-year-old Michael (David Kross) gets off because he feels sick and wanders the streets, pausing in the entryway of a nearby apartment building where he vomits. Hanna Schmitz (Kate Winslet), a tram conductor, comes in and helps him return home.
Michael, diagnosed with scarlet fever, rests at home for the next three months. After he recovers, he visits Hanna with flowers to thank her. The 36-year-old Hanna seduces him and they begin an affair. They spend much of their time together having sex in her apartment after she has had Michael read to her from literary works he is studying. After a bicycling trip, Hanna learns she is being promoted to a clerical job at the tram company. She abruptly moves without telling Michael.
In 1966 Michael is at Heidelberg University law school. As part of a seminar, the students observe a trial (similar to the Frankfurt Auschwitz Trials) of several women accused of letting 300 Jewish women die in a burning church when they were SS guards on the death march following the 1944 evacuation of a concentration camp near Krakow. Michael is stunned that Hanna is one of the defendants.
In the trial the key evidence is the testimony of Ilana Mather (Alexandra Maria Lara), author of a memoir of how she and her mother (Lena Olin), who also testifies, survived. She describes how Hanna had women from the camp read to her in the evenings.
Hanna, unlike her co-defendants, admits that Auschwitz was an extermination camp and that the ten women she chose during each month’s Selektion were gassed. She denies authorship of a report on the church fire, despite pressure from the other defendants, but then admits it rather than complying with a demand to provide a handwriting sample.
Michael realizes Hanna’s secret: she is illiterate and has concealed it her whole life. The other guards who claim she wrote the report are lying to place responsibility on Hanna. Michael informs the professor that he has information favourable to one of the defendants but is not sure what to do since the defendant herself chose not to disclose the information. Michael arranges a visit with Hanna in prison, but once there he leaves without seeing her.