Helga Pato, a young literary editor, returns home to find her husband overwhelmed by madness and winds up admitting him to a psychiatric clinic in the north of the country. On the return train journey, a stranger, trying to pass the time, asks her a question that pivots the narrative:
> "Would you like me to tell you about my life?"
That stranger is Ángel Sanagustín, a psychiatrist who is investigating what he calls the worst clinical case he has ever encountered. He centers his inquiry on Martín Urales de Úbeda, a paranoid man whose life is reconstructed through the account of Martín’s sister, Amelia Urales de Úbeda. Ángel pieces together a saga that begins with Martín’s alleged time as a fighter pilot in Kosovo, where he supposedly begins a relationship with Dr. Linares, a doctor working in a hospital for kids, who allegedly becomes involved as a female escort linked to the client Cristóbal de la Hoz in a gruesome plot touching on child abuse, child pornography, and organ trade.
As the layers unfold, it becomes clear that Martín’s life as a fighter pilot and his Kosovo ordeal are a fabrication: he is a former garbage man in Murcia who lost an arm on a brutal night shift and grew fiercely paranoid about his fellow garbage collectors. The strands intertwine further when Ángel visits the Urales de Úbeda family home near Las Ventas and discovers that Amelia is, in fact, Martín — someone who has accumulated years of unspoken garbage in the basement.
After Ángel finishes Martín’s tale, he steps off the train to fetch provisions and invites Helga to join him, leaving behind a red file full of stories as the train continues on its journey. This act of departure shifts the focus to Helga’s own backstory. The narrative then follows her disillusionment with a relationship with a bestselling author, followed by a romance with Emilio, a stand owner in Retiro. That relationship spirals into an abusive dynamic as Emilio gradually tries to mold Helga into something resembling a dog.
Helga’s darkest impulses surface when she contemplates harming Emilio with a hammer and feeding his brain to dogs; in the end, she resorts to poisoning, but the resulting drug-induced state leaves Emilio near catatonic, and she removes him from her life by taking him to the psychiatric clinic. Meanwhile, Helga becomes enthralled by the stories within the red file.
A separate thread recounts a failed Paris romance between Gárate, a man with severe faults in his view of life and relationships, and Rosa, a woman with one leg shorter than the other. Motivated by the red file, Helga resolves to publish these stories and sets out to locate Ángel. She travels to a house in Galapagar, where she is told that Ángel is not a psychiatrist at all but a man with a personality disorder. When she finally encounters him at a Las Ventas residence, the basement is littered with garbage and the confrontation erupts into a blaze of seemingly spontaneous combustion. Surviving the explosion and receiving a signal for a neurosurgical intervention, Helga boards another train and comes face to face with a man who bears a striking resemblance to Martín.
