The third book this series takes place while Harry Bosch is on trial (well the widow of a serial killer is suing the city for an unlawful killling by Harry). The case has been referred to in the previous two books so it is good to get around to knowing more about this. The serial killer, known as the Dollmaker had some fairly specific ways of staging the killing and during this trial a new body is uncovered that looks like the same killer but who was killed after Harry killed the suspected Dollmaker.
So was Harry wrong, did the police plant evidence to clear the crime and how did this new body fit in? All the twists and turns you expect from these thrillers so that just as you find out the truth you can think that you almost guessed the correct outcome.