In the Swedish hamlet of Hesjövallen, January 1960 nineteen people have been massacred. The only clue is a red ribbon found at the scene. Judge Birgitta Roslin's Andrén grandparents, and an Andrén family from Nevada are among the victims. She then discovers the nineteenth-century diary of an Andrén ancestor, a gang master on the American transcontinental railway, that describes brutal treatment of Chinese slave workers.