Duncan is in the throes of a mid-life crisis and searching for his own identity. His problems seem no different than other men facing the same issues, but as he struggles through a divorce and the challenges of co-parenting his children, Duncan soon realizes that he feels complete inside only when he begins to secretly explore a world of torture and death-a world that only he controls. Suddenly, Duncan's life is no longer normal at all. As Duncan deals with his newfound guilty pleasure of destruction and wickedness, his diary entries reflect a roller coaster psychological journey. Duncan grapples with the ramifications of what he is becoming, but at the same time, graphically describes the deaths of several of his victims. Clearly a man caught between his morals and an evil calling. Duncan leads a seemingly typical life during the day, but in the dark of night becomes a monster. Only one man suspects what Duncan is capable of-his best friend, Sudhir, a detective in the Palo Alto Police Department. Despite Duncan's cries for help penned on the pages of his diary, he becomes a master at hiding his transformation from "the guy next door" to a masterful serial killer.