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 investigates new evidence that may overturn Borders' conviction, but he remains convinced they locked up the right man. Lieutenant Billets is forced to deal with Crate and Barrel's role in the accident at the pharmacy crime scene. Bosch and Edgar track the pill mill van to an unexpected destination, while Edgar gets shocking news about Gary Wise.

As Bosch digs into the Skyler case, he becomes more convinced that the Olmer confession is false. Robertson zeroes in on the identity of the pharmacy killers. Seeking a connection to the pill mill, Bosch goes undercover and befriends a fellow vet. Pierce and Vega work a lead on Jose, Jr. Edgar discovers that Gary Wise's life was more troubled than it appeared.

Stranded in the desert without backup, Bosch closes in on his murder suspects and learns more about Clayton. Worried about her dad, Maddie turns to Billets for answers. Billets, in turn, confronts Edgar about Bosch's rogue mission. Pierce and Vega head to Bakersfield to find Jose Jr. Anderson gets a tip about police misconduct in the Borders case, and Cronyn implicates Bosch.

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.

Pierce and Vega find more body parts, and tie their murder to an ongoing RHD case. Maddie tells Bosch she sent the memo to Chandler, and doesn't regret it. Edgar knows who killed Gary Wise, but can't prove it. At his retirement party, Barrel springs his own surprise. Bosch commits to solving the murder of Daisy Clayton, Irving makes a big announcement, and Walsh returns for one last dance.

Nearly a year has passed and Bosch, still grinding on the Daisy Clayton murder case, gets called to the Lake Hollywood Overlook to investigate the murder of medical physicist Stanley Kent. Edgar runs a sting on his dirty cops, Maddie starts a new internship, and Chief Irvin Irving jumpstarts his mayoral campaign.