He takes the night train to Lisbon and carries with him a book by Amadeu de Prado, a (fictional) Portuguese doctor and essayist whose writings explore the ideas of loneliness, mortality, death, friendship, love, and loyalty. Chafing against his solitary routine for the first time in his life, Gregorius becomes obsessed by what he reads and restlessly struggles to comprehend the life of the author. His investigations lead him all over the city of Lisbon, as he speaks to those who were entangled in Prado's life. Gradually, the picture of an extraordinary man emerges  a doctor and poet who rebelled against Salazar's dictatorship.