Nick and Andy go missing while working under cover to infiltrate a meth pipeline; Swarek and the other officers find themselves in the middle of a rescue operation; Andy works to deal with all the change going on around her.

On her first day back, Andy is forced to work a bank robbery case with newly promoted Swarek; a distraught woman gives Nick perspective on his life with Gail; a bombshell is dropped on Noelle.

Andy and Officer Cruz butt heads when a disturbed woman forces them to make a crucial decision; an armed burglar is sought after a string of ATM robberies; Dov and Chloe have to work together.

During a routine traffic stop, Gail and Andy find a teenage boy bound and gagged in the trunk of a car; Oliver, Chris and Swarek track a gunman.

When an arrest reveals that drugs contaminated with a deadly bacteria have hit the street, the squad rushes to control the situation; Marlo reveals a shocking secret; Dov suspects Chloe of hiding secrets.

When the investigation of a missing girl is linked to a past case, Detective Luke Callaghan comes back to help with search; Traci realizes she needs to get past Jerry's death; Sam and Andy face their past.

When a missing persons case is reopened, Swarek teams with his training officer to solve it; Chloe and Dov deal with a witch and her client.

A robbery on a casino-bound bus filled with seniors threatens Frank and Noelle's wedding; Traci loses Noelle; Andy and Nick share an intimate moment.

The squad searches for Chris' son Christian after he is kidnapped.

A routine drug bust turns into Traci's first murder case; Swarek, Oliver, Chris and Dov spend a weekend at Oliver's cabin; Andy and Sam both have confessions to make.

Andy finds out Marlo has been carrying out an unauthorized investigation into a pedophile; the drug sweep Traci is overseeing takes an unexpected turn when Sam leaves to help Marlo.

When Andy and Chloe respond to a routine 911 call, they are blindsided by an unseen shooter out for revenge.

Following violent, targeted attacks on 15 Division, the officers must piece together a past crime in order to find Oliver; the shooter's plan is revealed.

A bomb explodes in a parking garage. The 15 Division must stop the suspect.

The officers of 15 Division work to track down Ted McDonald. But even after catching him, they realize Ted has more targets set to explode out there. The clock is ticking…

Andy and Sam return to work; Andy is attacked at Traci's place and Sex Crimes Unit tries to take over the case

Andy contemplates her future with Sam after learning heartbreaking news. Andy meets a teen in need of protection.

A riot breaks out at a women’s correctional institute while Andy, Juliet, Nick, and Gail are there to transfer prisoners. They end up separated and in a lock-down situation that finds Andy and Juliet trapped with a woman desperate to prove her innocence.

Nick receives new information on his tragic past, and goes off the grid to track someone down; Nick is forced to tell Juliet about his secrets.

Andy and Sam are shocked to learn that Oliver is the prime suspect in IA’s corruption investigation into 15 Division. What’s worse, they only have until end of day today to find Chris Klem – the missing explosives-dealer – and clear Oliver’s name before he takes the fall.

As the officers of 15 Division try to move on from the corruption scandal, a heat wave hits and Jarvis opens the division to the public as a cooling station. Andy heads out with a very-pregnant Marlo to find a volatile woman who’s gone missing after group therapy, but neither Andy nor Marlo are prepared when Marlo suddenly goes into labor.

Dov and Andy cover a music festival where a girl ends up dead due to drugs. Gail goes to court and is unsure whether lying for her brother is the right thing to do. Nick gives Juliet another chance.