After three years out of the LAPD, Harry Bosch returns to find a very different place to the one he left.  A new Police Chief has been brought in to clean it from top to bottom.  Working with his former partner, Rider, Bosch is assigned to the Open-Unsolved Unit, working on thousands of cold cases.  They are the Closers, applying new techniques to old evidence.  They are handed a politically sensitive case when a DNA match connects a white supremacist to the 1988 murder of a sixteen year old girl of mixed race.  Does the case have a racial angle?