Starting over isn't easy, especially for small-town guy John Nolan who, after a life-altering incident, is pursuing his dream of being a police officer. As the force's oldest rookie, he’s met with skepticism from some higher-ups who see him as just a walking midlife crisis. Throw in a workplace romance, a hostage situation, and some tough love from their new training officers, and the latest Los Angeles police rookie class has an uphill battle ahead of them.

After Nolan and Talia lose control of a crime scene, they begin to debate whether people are fundamentally good or bad and what that means for a police officer. Lucy is concerned Tim is enabling his wife’s destructive behavior and not taking care of himself.

Nolan, the rookies and their training officers get involved in a competition that pits them against each other. Chen notices Bradford is obsessed with winning at all costs.

Officer Bradford’s wife, Isabel, is found shot but alive and he vows to track down the man responsible. Meanwhile, Officer Nolan must protect his home and the truth after a home invasion attack.

The rookies become the prime suspects after it is discovered a large sum of money used in a drug bust has gone missing.

When a prison bus crashes, all units must respond as some inmates face severe injuries while others seek an opportunity to flee. In the wake of the accident, Officer Nolan tries to impress an FBI hostage negotiator while tracking down an escaped convict.

When one of their colleagues is arrested by Internal Affairs for lying on the witness stand, it leads to the release of three felons whose cases he worked on and the team being asked to check in on them now that they are free. Meanwhile, Officer Nolan finds out he is being sued by a man who claims he used excessive force which led to an injury.

Danger is ever-present as the officers of the Mid-Wilshire precinct grapple with the aftermath of a plotted attack on the city of Los Angeles, leaving Officer Bradford fighting for his life.

Officer Nolan gets off to a rocky start after being introduced to his new training officer, Nyla Harper, who has an unconventional approach to police work after her stint as an undercover detective. Meanwhile, Officer Bradford struggles to think of an appropriate birthday gift for Rachel, and Officer Lopez finds herself navigating a case that triggers a personal memory.

John and Jessica’s relationship gets a lot more complicated after she delivers some surprising news. Meanwhile, Officer Bradford and Office West are assigned a community policing project helping out the Watts Rams as volunteer coaches at their fall clinic, along with Rams players Eric Weddle and Robert Woods.

Officers Chen and Bradford respond to a call at the Los Angeles auditions of “American Idol,” and Officer Chen ends up facing Ryan Seacrest and the judges. Meanwhile, Chen befriends a reporter whose motives are not clear.

Their rookie year is coming to an end and officers Nolan, Chen and West are about to be squeezed harder than ever before as their training officers evaluate whether they are truly ready for the job. Meanwhile, after one of their rookie classmates is involved in a shooting, the team uncovers some unsettling evidence .

Desperate to break free from his connection to Elijah, Wesley tries to plant a listening device in his office to incriminate him; Officer Bradford and his sister, Genny, learn an unsettling truth about their father.

Officer Nolan and the LA division of the FBI enlist the help of FBI trainee Simone Clark when one of her former students is suspected of terrorism following an explosion at a local power station.