Helga, editor in low hours, has just admitted her husband to a psychiatric hospital. On the train back, a stranger is introduced as Ángel Sanagustín, a psychiatrist who works in the same clinic investigating personality disorders through patients' writings. During the journey, Ángel tells Helga the story of Martín Urales de Úbeda, an extremely dangerous paranoid patient obsessed, among other things, with trash.