Bangkok, 1975. Charles Sobhraj is a thief and a conman. He targets young travelers on the Asian Hippie Trail and ruthlessly exploits their innocence. When Herman Knippenberg, a junior diplomat at the Dutch Embassy in Bangkok, opens a letter from a man in The Netherlands worrying after the whereabouts of his sister-in-law and her boyfriend, he accidentally walks into Sobhraj's intricate web of crime.