When the department's sorter takes a call from an anonymous witness to a cold case murder, she takes it straight to Harry Bosch who finds the accused in San Quentin. He's locked away for a different murder but only a few months away from a parole hearing which is likely to see him walking free. New methods find DNA on the murder weapon but having sat in an archive for 20 years, it's not strong enough to take to court. To keep him behind bars, Bosch has no choice but to find the witness who doesn't want to be found.
