When Andy and Chris make an untimely arrest, they unknowingly compromise a major drug bust. Andy steps up, attempting to salvage the operation by going undercover with Swarek, but a critical change in plans puts both of their lives in danger. Back at the station, Dov learns more about his girlfriend than he wanted to know—forcing him to chose between police work and his love life.

It's judgment day for the rookies, who soon will learn whether or not they've passed their evaluations and can keep their badges. Before she hears her fate from Staff Sgt. Frank Best, Andy has a harrowing experience involving the suspicious death of an unidentified girl that causes her to consider leaving the force.

After stumbling on gruesome evidence that Andy's ex-cop father may have committed a murder during a drunken blackout, Andy and Swarek furiously search for proof of his innocence. Meanwhile, Chris and Dov show they're not superhero crime fighters when a masked vigilante dressed like a caped crusader robs their squad car and the unintentional consequences help a drug dealer.

Andy and Swarek try to put their tense personal relationship aside during a routine prison transport, but their frustrations explode when the inmate escapes and they're forced to chase him down. Back at the station, Dov and Gail seek answers in the mystery of an amnesiac John Doe, and Chris and Traci help Detective Barber reconstruct the missing notes from a crucial court case.

Chris and Gail's investigation into a messy highway accident leads to the discovery of a license plate matching an Amber Alert for a missing nine-year-old girl. Division 15 embarks on a massive manhunt to find the girl and the car's missing driver. Meanwhile, an intense interrogation of the parents uncovers disturbing evidence. More secrets unravel, as the entire division races the clock to find the young victim - hoping it's not too late

When Andy and Chris investigate a vicious nightclub beating, the probe takes a surprising turn. The two rookies must make a gut-wrenching decision that will send shock waves through the division and jeopardize their careers. Meanwhile, things get up close and very personal as Luke and Sam compete during a retraining exercise.

A severe heat wave wreaks havoc on the city, making life on the streets even more perilous for the new members of the squad. The danger multiplies with the discovery that a serial rapist may be on the loose. Amid the chaos, Andy is cut off from her backup during a sudden citywide blackout and is challenged with taking down a vicious predator -- alone. Meanwhile, Andy also makes an unexpected romantic decision that's certain to complicate her life on and off the job.

A fatal traffic accident involving an elderly man and a cyclist may not be as open and shut as it seems, and Andy's romance with Detective Luke Callaghan also seems headed for a collision after she objects to how he handles a young murder witness with a bullet lodged in his head.

Andy and Traci are part of a massive first response to a home invasion at an upscale address - an incident that ends up spilling many of the officers' personal secrets. Once the crisis appears to be over, Traci hurries off to handle a personal emergency, leaving Andy alone to confront the armed predator, a surprisingly volatile thief left prowling around the house.

Andy's undercover skills are put to the test when she's brought in to pose as a prostitute during a citywide sting operation. But a bid by Andy and Dov to impress Sergeant Boyko with their initiative backfires when the two rookies put a vulnerable informant's life in jeopardy, and it's left to Andy to infiltrate a risky gun deal in progress to save her.

While other rookies get ready to duke it out at the police department's annual "Fite Nite" charity event, Andy wrestles with a dilemma of her own: Should she keep a promise to protect a domestic abuse victim who has been repeatedly let down by the system - even if it means breaking police protocol to do the right thing?

As the other rookies attempt to hunt down a violent escaped convict, Andy gets a lesson in the dangers of undercover work when she and her training officer, Detective Sam Swarek, search for a missing informant whose cover has been blown. Swarek's rogue tactics on the job aren't all that Andy finds troubling -- there's also a surprising, undeniable attraction between the two of them

Five young, ambitious cops, fresh out of the Academy, are plunged into the world of big city policing on their very first day on the job, a world where even the smallest mistake can have life-or-death consequences, coupled with some serious emotional fall-out. Andy McNally is the soul of this close-knit group. She and her uniformed family of boyfriends, best friends, mentors and competitors will undergo extreme trials and tribulations, share their triumphs, cherish their camaraderie and revel in their competition. These rookies are about to learn that no amount of training can prepare them for life on the street.