LAPD detective Renée Ballard and Harry Bosch work together to hunt the killer who is Bosch's 'white whale' - a man responsible for the murder of an entire family.

A year ago, LAPD detective Renée Ballard quit the force in the face of misogyny and endless red tape, but then took back her badge after being offered her dream job: building a new cold case unit. She makes Bosch an offer - if he works as a volunteer investigator for her, he can he can pick up the cold case that has haunted him for years, the murder of an entire family by a psychopath still walking free.

There's just one catch: they must first solve another murder.

Can Harry and Renée put aside their old resentments? Is Harry still at the top of his game? What do you do when faced with a child-murderer who may forever evade justice?

United by single-minded determination, Ballard and Bosch blaze fresh life down cold trails in their pursuit of justice.