At the beginning, the novel presents itself as a report that an unnamed narrator weaves together from court documents and police reports created on the basis of the proceedings against Katharina Blum. She is accused of murdering Tötges, a journalist from the tabloid Zeitung, who was investigating her connection with the alleged member of a terrorist organisation, Ludwig Götten. Katharina Blum met him at a party, and after he was arrested and questioned for his supposed involvement in a politically motivated bank robbery and membership in a terrorist organisation, the police trace leads them to Katharina, who had spent several days with him and whom they believe helped him go into hiding and escape. The sensationalist tabloid Zeitung, despite the lack of evidence, begins fabricating a story about Katharina Blum as an accomplice to a terrorist; they interrogate her neighbours and exaggerate their statements or entirely adapt them to the story of her immoral life that they themselves invented. It soon becomes clear that Ludwig is not a terrorist at all and that his role in the bank robbery was minor and marginal, but this does not stop the spread of falsehoods about Katharina. She therefore decides on a radical response. She calls the journalist Tötges and arranges a meeting with him to conduct an interview, and when he arrives she kills him with a pistol. When, at the end of the novel, the case compiled from police and court files is concluded, the narrator ends his account by warning of the consequences of media manipulation and the abuse of tabloid journalism.

Böll constructs his novel as a search for truth that attempts to establish itself between two textual extremes. On one side is the police report, which derives its authority from the state apparatus and the judicial system that seeks to determine what happened to Katharina Blum during the few days in which she killed a journalist. On the other side is the tabloid, which fabricates a story about Katharina Blum that is false from her perspective, a view shared by the narrator, who arranges the police records and presents them to the reader as a novel. Although, as noted, the origin of violence lies in the untruths produced by the tabloid press, it would be extremely imprudent to fully side with the police report as an unquestionable insight into the truth of events. A legal process in which guilt or innocence is proven is not a reconstruction of truth, but rather a construction of a possible truth that claims to be based on positive and objective facts. Since objective facts, if such things exist in the construction of stories, are scarce and unusable, it is logical to turn to literature as a specific discourse which, precisely because of its obvious disinterest in truth, proves to be the most truthful.

Literature thus places itself in an uncomfortable position between the police report and the tabloid article through its ability to incorporate various discourses and texts, openly pointing to them and drawing attention to them. The narrator therefore directly engages in a critique of his own story: “Before the final manoeuvres of turning, diverting, and deflecting are set in motion, one must allow, so to speak, a technical remark. Too much happens in this story. It is a painful, barely manageable mode of narration, overburdened with action, to its own detriment.” The technical remark in this quotation is a comment on the narration and organisation of the story of Katharina Blum that neither of the other two texts would ever permit.

The Lost Honour of Katharina Blum is not a political novel simply because it addresses a specific political moment in West Germany in the mid-1970s marked by terrorist groups fighting against the state. It is political because, parallel to narrating the story of a young woman accused of aiding a potential terrorist, it also writes the impossibility of writing and narrating her story, thereby becoming more credible and convincing than those types of discourse that tirelessly persuade their readers of their own truthfulness, a truth that is always betrayed.