Part First
The narrator introduces himself. He is an English teacher in Geneva, Switzerland. He tells us the story of Kyrilo Sidorovitch Razumov, who is a student at the University of St. Petersburg in the 1910's. He has no family to speak of. We learn the Minister of State has been assassinated, along with several innocent bystanders, in a bomb blast. When Razumov goes to his dorm, he finds Victor Haldin, a fellow student who claims responsibility for the terrorist attack. He needs help escaping.
Razumov is thrown into confusion by the request. He shares none of his fellow student's political views, but he likes to be helpful. He must find Ziemianitch who was originally supposed to help with Haldin's escape, but when he does, he has a violent panic attack and brutally assaults him. He betrays Haldin to the police and they set up a sting operation. Later that night, he is caught, but Razumov wonders if he did the right thing. The police summon him for questioning and he realizes that perhaps they will think he is a revolutionary, too. The police say they have already searched his apartment and he is free to go—Haldin has already been hanged to death for his crimes.
Part Second
Haldin's sister, Natalia, lives in Zurich where they wait for Haldin's arrival, expecting that he escaped from Russia. The narrator explains that he found the story in the paper and broke the news to Natalia himself, which she takes in stride, though Haldin's mother is distraught. Natalia also learns that Razumov wants to visit Geneva, and she has always wanted to meet him.
She meets Tekla, an abused partner of Madame de S—, who owns a decrepit house called Chateau Borel. Tekla explains his life story, but when Razumov arrives, Natalia excitedly introduces herself, and Razumov privately feels guilty for her loss. Although Razumov is no revolutionary, his sarcasm is misunderstood, and Tekla enlists himself in Razumov's non-existent revolutionary plans for Russia.
Part Third
We flash back to Razumov before his trip to Geneva. He stayed with Sophia Antonovna, who works for Peter Ivanovitch, a famous revolutionary who lives at the Chateau Borel. Upon her arrival, he takes long walks with Natalia, but we learn that he is secretly a spy for the Russians. Some people admire his cool leadership, but some people notice he seems to be hiding something. Ivanovitch is thirsty for female attention and approval. We learn from conversation that Ziemianitch has killed himself, so no one suspects Razumov—they assume Ziemianitch was the spy.
Part Fourth
In a flashback, we learn how Razumov became a spy. When the Russian police searched his apartment, Mikulin, the chief, decides Razumov is useful to him. He studies his thoughts by reading his essays, and when he asks Razumov to be a spy, Razumov says yes.
We flash forward. Razumov is writing his first piece of intelligence, a report of his findings, which he will send to Mikulin. On his way to the post office, the narrator himself approaches Razumov, but Razumov doesn't notice him. When Natalia finds Razumov, she is urgent—there is new activity in the revolutionary movement. Razumov writes a report in his room, writing down the new details, but instead, he writes to Natalia and explains to her that he has fallen in love with her, and he confesses the truth to her in his letter. At a revolutionary party that night, he stops the crowd and makes an announcement—he, not Ziemianitch, betrayed Haldin. They beat him and break his eardrums. In the epilogue, Haldin's mom dies and Tekla cares for Razumov who is now permanently disabled.
