Detective Harry Bosch learns the DA's office is examining new evidence which threatens to overturn an old case, potentially jeopardizing all of Bosch's other convictions. Meanwhile, a robbery turned murder at a local pharmacy exposes an opioid ring that drags Bosch down a dangerous path.

Bosch and Edgar uncover more details about the pharmacy murder and the opioid operation, while Detective Robertson works a tandem homicide. As Bosch pushes back against the deathbed confession at the heart of Borders' petition for release, he enlists the help of a longtime adversary. J. Edgar tries to persuade a former CI to cooperate with an investigation.

Bosch continues his hunt for the pharmacy killers. Edgar confronts possible suspects in Gary Wise's murder. Hoping to rattle some cages, Bosch pays a surprise visit to an old nemesis. Chief Irving considers a run for mayor.

Edgar interviews Clayton, desperate for details on Bosch's location in the desert. Meanwhile, Stones and Carter tell Bosch he's going home, but ominously take him up in the plane by himself. Billets resolves to turn a blind eye to the falsified crime stats. Crate plans Barrel's surprise retirement party. Irving makes his case to the DA, and Edgar gets closer to finding Bo Jonas.

Chandler and Bosch locate Spencer, and try to pressure him to flip. At Borders' habeas hearing, Chandler gains standing for Bosch and reveals the Cronyns' conspiracy. Edgar connects Marcos and Arias to a shady Haitian under CIA protection. Irving considers his future. Pierce and Vega catch a gruesome new homicide. Bosch has one remaining loose end to tie up in the Skyler murder.

New Year’s Eve 2019. While Los Angeles celebrates, a fire breaks out in an East Hollywood apartment building killing several residents including a ten-year-old girl. When it’s determined to be arson, Detective Harry Bosch arrives on the scene but his partner, Detective Jerry Edgar, is noticeably absent.