Nolan teams up with new night detective Nick Armstrong for a murder investigation case that results in an unexpected reunion with a former love interest.
On Captain Andersen’s orders, Officer Nolan and Sergeant Grey are paired up for the day on patrol. Additionally, Nolan’s son and Grey’s daughter visit their dads on the job and see them in action. Meanwhile, Officer Chen is paired up with Captain Andersen, and Officer Bradford tells Chen to protect her at all costs.
Nolan takes his son’s fiancé, Abigail, on a ride-along after she shows interest in becoming a police officer. Meanwhile, Jackson’s relationship is becoming complicated at work.
Officers Nolan and Harper investigate a murder which may have national security implications, while Officer Bradford must confront his past when he crosses paths with a homeless veteran.
Sergeant Gray informs the rookies that they must track down a specific set of crimes in a 48-hour period in order to qualify for their final exam. Meanwhile, Officer Nolan and Officer Bishop answer a silent alarm call at will.i.am’s house.
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.
Officer Nolan gets a lesson in respect after his arrest of a gang member leads to a free-for-all on his life. Meanwhile, Officer Chen and Officer Bradford pull over Mario Lopez, who thinks he can talk his way out of a traffic violation.
The rookies are temporarily paired with new training officers, and Officer Nolan is paired with Officer Lopez. When Nolan and Lopez track down an escaped criminal, they discover a little kindness goes a long way. Meanwhile, Jackson is forced to face his fears when he is partnered with Officer Bradford, while Officer Chen and Nolan must face a hard truth.
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 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.