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

When Dov and Chris discover a missing girl's body in a ravine, Detective Luke Callaghan returns to oversee the investigation; when the officers learn that Gail has been abducted, they rally to track down her captor.

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.

Andy, Dov, Gail and Nick undertake a risky plan; Traci shadows Steve Peck, hoping to calm her fears about his involvement in the bombing.

With the 15 Division restructuring looming, Andy and Sam’s wedding comes just in time for the gang to celebrate one last hurrah. But when Andy is taken off-course by a hitchhiker and then stranded on the side of a dead-end road with a dying man, she finds herself with no way to get help – or let Sam know she hasn’t bailed. Will she save the man’s life? Will she make it to her wedding?

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…

Blaming herself for Swarek’s mysterious disappearance and fearing for his life, Andy struggles to find a lead in the case. Will Andy and the other rookies find him in time? Little do they know that shocking events triggered by this investigation will incriminate one of their own and may also put an end to Andy’s career.

In the aftermath of the night's traumatic events, Andy and Dov try to pull themselves together at an all-night diner, but are caught off-duty and off-guard in a volatile diner hold-up. Meanwhile, the weary officers at 15 Division struggle to contain the evening's collateral damage under the watchful eye of a tough new Inspector.

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.

Andy's world explodes by a seemingly senseless act of violence during a concert shooting. When she sets out to unravel the details, she comes into direct conflict with Luke's former partner, Detective Jo Rosati, a new detective with Division 15. As Rosati investigates the case, sparks soon fly between her and Luke.

When Traci and Andy are sent out on an undercover training exercise, they stumble upon a young woman who is about to die of an overdose. Meanwhile, Dov finds himself on a “ride-along” with a drug dealer and old friend of his deceased brother. Back at the station, Chris and Gail deal with a teenage boy they found tied up at a graveyard; sifting through the wreckage of their relationship, to try to get to the bottom of a bullying situation.

The officers try to prevent dangerous fallout when a laptop containing sensitive information is stolen; a wedge is driven between Sam and Andy.

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.

Strange happenings and a full moon rattle the rookies. Andy and Sam investigate the theft of some severed heads from a medical lab. A particular man catches their attention as a suspect with his obsessive behavior. While trying to protect a young woman who could be the next target, Andy puts her life and Luke's in jeopardy.

As the officers of 15 Division try to hunt down the killer of Brian Gowdy, Andy and Sam go on the road to interview a list of inmates at Millburn Penitentiary. All are known associates of the prime suspect; one person on that list happens to be none other than Jay Swarek, Sam's elusive father.

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.

Andy and Chris accidentally screw up one of the biggest drug busts of the decade when they arrest one of the players. In an effort to save the operation, Swarek and Andy go undercover to make the drug buy. When Andy realizes that their bait and switch has created an ambush that will endanger Swarek’s life, it’s all hands on deck as the coppers of 15 Division rush to save the life of one of their own.

Detectives Callahan and Rosati are at odds over how to correlate and interpret the facts of two vicious crimes. Luke feels strongly that the latest woman attacked on her watch is connected to an unsolved rookie's murder, but his erratic behavior gets him kicked off the case. Andy may be in serious trouble when Luke urges her to follow through with his hunch on the crimes.

When a pattern emerges among several cases of missing women, Gail goes under cover to investigate; Dov and Chris discover a body, leading them to believe Gail is in danger.

A violent pedophile escapes during an emergency hospital visit and abducts a girl; Andy faces a serious decision; Chris considers a transfer.

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

When a tenement-building shooting leads to the discovery of an executed gang leader, 15 Division must race to find the killer before a gang war breaks out. As the murderer zeroes in on the one witness who can tie him to the crime, Andy and her rookie, Duncan, are put to a life-and-death test of true police heroism.

When 15 Division goes undercover at a club-land bar that's a possible hub for illegal handguns, Chris's erratic behaviour and concern for a specific drug dealer make Dov suspicious. Meanwhile – after learning Duncan has made serious professional allegations against her – Andy decides to help Sam with a missing person's case that takes a dark turn.

Dov suspects Chris isn't ready to get back on the right track; Steve tells Traci he's about to raid a gambling den frequented by her husband.