Separated in three apparently independent chapters, Advantages of Travelling by Train tells the story of editor Helga Pato, a forty-something woman who by chance meets psychiatrist Ángel Sanagustín in a train ride, who tells her (first chapter) the story about one of his patients, Martín Urales, who enlisted in the army was sent to fight in the Kosovo War where he met Dr. Linares, a determined and compassionate woman that trying to create a child hospital to heal war damaged is forced to make a terrific deal: in exchange to have the hospital she wants, Linares must bring a child per month to her benefactors to film adult and snuff movies. Returning home after he was fired from army to attempt alert his superiors, Martín's aging father rejects the story and rejects his son, forcing Martín to the exile. In this point Sanagustín downs in a train station to buy candies but have no time to return, and Helga finds Sanagustín's folder in front of him. Reading the medical record of the patients (chapter two) Helga remembers her own story when, after to split with a famous writer, she met Emilio, an apparently quiet and calm man to start a relation with him, being gradually humiliated and degraded by a schizo Emilio obsessed to turn Helga in a dog and treating her as it. Drugging him to escape a few days with her mother and recover her freedom, Helga returns to find a delirious Emilio watching his own stool, getting enough reasons to intern him in a mental hospital just before to meet Sanagustín. Fascinated by the folder (chapter three), Helga decides to locate him and discover the secrets behind the folder's medical records, learning than the reality about Sanagustín and Martín is more twist and dangerous that she could imagine.