O primeiro dia de trabalho para um policial novato não vai ser fácil, especialmente quando seu oficial de treinamento é resistente-como-pregos, o Oficial Veterano John Cooper. Enquanto isso, Det. Lydia Adams investiga o desaparecimento de uma menina que sumiu enquanto jogava bola.

Uma investigação é aberta quando os oficiais Cooper, Sherman, e Brown encontram um bebê abandonado no meio de um cruzamento. No entanto, o caso se revela demasiado perto de casa para o Det. Adams, cujo envolvimento com a investigação obriga a lidar com as questões do passado. Enquanto isso, os detetives Bryant e Moretta se encontram em uma situação difícil quando eles parecem não conseguir reunir fundos suficientes para colocar um adolescente sob proteção policial para sua segurança.

Oficial Sherman revela detalhes de seu passado que explicam a sua motivação para ser um policial. Enquanto isso, o Oficial Brown questiona sua parceria com a Official Dewey quando ela se torna chocada e não consegue fazer o seu trabalho.

Os Detetives Bryant e Moretta são convocados para um beco em Los Angeles, onde o corpo de uma mulher não identificada está sendo usado por vândalos de rua para praticar tiro ao alvo. Enquanto isso, Det. Moretta revela a verdade sobre sua irmã.

Os Detetives Moretta e Bryant vão ao auxílio de Det. Salinger, quando ele se choca contra um poste de luz e os membros de uma gangue roubam sua arma. Enquanto isso, Det. Adams é surpreendida quando um homem se expõe fora de sua casa.

Quando os detetives Adams e Clarke investigam ladrões de jóias que estão mirando casas em Bel Air, O Oficial Sherman se envolve pessoalmente quando ele descobre que ele conhece uma das vítimas. Entretanto, conforme Bryant e Moretta preparam Janilla para o julgamento, Det. Bryant usa meios não convencionais para garantir sua segurança.

Depois que um membro da gangue de Marta Ruiz Avenue é encontrado morto, o detetive Bryant convence a Det. Adams à ajudar Janilla. Enquanto isso, o fosso entre Det. Salinger e sua filha adolescente continua a se aprofundar.

Officer John Cooper clashes with his new boot, Gary Steele, a vet from Afghanistan. Lydia struggles to balance detective work and motherhood. Ben Sherman falls in with a sketchy crowd of cops, while Sammy Bryant is trapped in a hellish custody battle with Tammi.

After Mendoza is injured in a drive-by, Ben takes it upon himself to solve the case, much to Sammy's dismay. Lydia regains her footing as a detective while investigating the murder of a female boxer's husband. Tensions between Cooper and Steele finally come to a head during a traffic stop-gone-sideways.

A breakdown in the LAPD's dispatch system makes a difficult job even harder for the cops, all of whom are already grappling with communication issues. Lydia, in a moment of weakness, reaches out to her old flame, Terrell. John is assigned a new partner; Ben and Sammy's partnership is strained just as Ben makes a romantic connection on the job.

Lydia and Reuben track the killer of a man whose body was slow cooked down to the bone. John and Lucero settle into their new friendship during a day filled with strange calls. Ben and Sammy respond to an insane bank robbery in which the suspects throw cash out into the streets as they make their escape in a getaway car.

John is forced to think about what life will hold for him once he leaves the LAPD. Lydia connects with a man she sent to death row earlier in her career. Much to his chagrin, Sammy becomes a tabloid celebrity for the day after a very public act of heroism. Ben makes a dubious decision to get a drug dealer arrested. And a foot pursuit puts Dewey in danger.

The day’s events bring all of our cops face to face with some of their greatest fears. The death of a baby shakes Lydia to her core. Sammy is questioned by I.A. about his altercation with Tammi. A difficult day on the job causes Cooper to seek solace in Hicks but finds none. Ben becomes more deeply involved with Brooke while continuing to see Elena.

John takes drastic measures to try to save Hicks while being confronted with demons from his past. Sammy’s lie about the tape weighs heavily on his conscious. Lydia and Ruben track down a John Doe. Ben’s relationship with Elena becomes more serious.

The funeral of a major drug dealer brings gangsters of all kinds out of the woodwork, there is chaos in the streets but as our cops learn sometimes the greatest threats come from within. Lydia and Ruben investigate the drug related murder of Sgt. Hill’s son; they discover police corruption in the process and clash over how to handle it. Ben suspects that Sammy did not destroy the tape and decides to take matters into his own hands with tragic consequences. John sinks farther into his loneliness.

Chaos prevails in the city of angels when Cooper and Lucero are kidnapped and held hostage by a pair of tweakers. All of our cops join the frantic search to find their brothers in blue before it is too late. Sammy searches for Strokeface. Ben tries to throw Sammy off the trail while simultaneously dealing with an increasingly irrational Brooke.

John copes with the aftermath of his kidnapping. Sammy closes in on the real robbers. Lydia continues to pursue John’s kidnappers and becomes more intimate with Russell.