Detective Harry Bosch investigates a cold case and the murder of a city councilman's son. The cases are unrelated but they twist around each other like the double helix of a DNA strand. One leads to the discovery of a killer operating in the city for as many as three decades; the other to a deep political conspiracy that reached back into the dark history of the police department.

Vail's boyfriend, Detective Robby Hernandez, has seemingly disappeared into the dense air of a Napa Valley evening. There are no clues to his whereabouts, other than a blood stain--and potential connections to a serial killer operating in the wine country.

"Martha Ratliff conceded long ago that she'd likely spend her life alone. She was fine with it, happy with her solo existence, stimulated by her work as a librarian in Maine. But then she met Alan, a charming and sweet-natured salesman whose job took him on the road for half the year. When he asked her to marry him, she said yes, even though he still felt a little bit like a stranger. A year in and the marriage was good, except for that strange blood...