The Enemy Within

Officer John Nolan is once again face-to-face with serial killer Rosalind. Officers Bradford and Chen work undercover with Detective Lopez and the Las Vegas Police Department to arrest leaders of a major criminal enterprise.

Officer John Nolan moves closer to his new role as a training officer; John must uncover the truth about another officer's suicide; Lucy's successful undercover assignment earns her an invitation for specialized training.

Officer John Nolan is assigned his first rookie, Officer Celina Juarez, whose unconventional approach to police work poses a unique challenge for him.

Rosalind returns with a vengeance and Bailey's life is left hanging in the balance; Nolan is forced to make a deadly decision after a harrowing ultimatum.

Nolan and Juarez are on the hunt for a fugitive after a car incident goes awry; a past injury comes to haunt Tim and Lucy comes through during his time in need in more ways than one.

Nolan and Celina investigate a cash deposit linked to an old DEA case; Wesley grows increasingly concerned about his deposition and is shocked when he realizes Elijah's attorney is a familiar face from his past.

Officer John Nolan and Celina witness a shooting and realize the victim was already dead; Bailey has been feeling off-center since the proposal, leaving Nolan to wonder what he can do to make her feel better.

Officers John Nolan and Celina Juarez are in a race against time to stop the source of an explosive rampage.

Officer John Nolan and the team investigate the unexpected death of a suspect in police custody; Sgt. Grey and his wife, Luna, go to New York to visit their daughter, Dominique, only to realize she never made it home from the night before.

Detective Nyla Harper and James find themselves in the middle of a bank robbery, which leads the entire team on a citywide manhunt; Tim and Lucy go on their first date.

The search for a missing boy leads the team into the middle of a dangerous drug war between two rival gangs.

Nolan and Celina must stand guard at a hospital after a dangerous prisoner needs surgery; Aaron, Lopez and Harper look into a string of robberies; Tim and Lucy consider how their secret relationship will affect their work; Lopez gets unexpected news.

In the midst of a heatwave and a citywide blackout, Nolan and Aaron follow increasingly large leads after they discover criminals hiding at the station; Chen makes an alarming discovery after being called to a scene with a pungent smell.

Officer John Nolan and Bailey search for a mystery gunman after a shooting hits a little too close to home; Aaron struggles to live within his means; Wesley suspects that a judge is taking bribes.

With help from the FBI, Lopez puts everything on the line to help Elijah Stone take down a gang leader in exchange for her safety; Nolan and Bailey must deal with the secrets and shady dealings his late mother left behind.

The team must stop a militia from detonating a highly combustible truck in their possession; Nolan, Thorson, Juarez and Harper search for three men who may have been exposed to Ebola.

Now that Elijah and Abril have become allies, the team must rely on Monica, Elijah's lawyer, to uncover their plans; Officers Nolan and Juarez reopen her sister's case and discover a discrepancy that leads them on a new trail.

When Dim goes missing, Officer Chen and Sgt. Bradford, along with the CIA, set out to find him and enlist the help of Juicy.

The team investigates a pattern of kidnappings, which leads them to a discovery that hits close to home with one of their own; Lucy and Tim's relationship is put to the test as they begin to feel the hard hours of their jobs.

Officer Tim Bradford’s ex-wife returns and asks the team to help her save someone from her undercover past. Isabel’s return also creates additional pressure in Lucy and Tim’s relationship as they assist in the search.

Officer Lucy Chen goes undercover to infiltrate an illegal firearm operation; Detective Harper and Officer John Nolan work together to solve a mystery involving severed limbs found around the city.

After one of their own is shot, the team suffers a series of close calls and realizes their division may be a target for a group of masked assailants.