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.

It's a day of firsts as Oliver gets promoted to Acting Staff Sergeant and Andy is tasked with training 15 Division's newest rookie, Duncan Moore. But when Andy and Duncan respond to a messy homicide at a pawnshop, it's clear this rookie is going to give Andy the challenge of a lifetime.

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.

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.

Oliver prepares Andy to defend herself at Duncan's dismissal hearing.

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.

When the Division helps tenants move out of a condemned subsidized-housing complex, they discover a badly beaten man in one of the empty units.

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…