following Detective Renée Ballard (Q) as she leads the LAPD's new and underfunded cold case division, tackling the city's most challenging long-forgotten crimes with empathy and relentless determination. As she peels back layers of crimes spanning decades, including a serial killer's string of murders and a murdered John Doe, she soon uncovers a dangerous conspiracy within the LAPD. With the help of her volunteer team and retired detective Harry Bosch (Titus Welliver), Detective Ballard navigates personal trauma, professional challenges, and life-threatening dangers to expose the truth.