Triumph turns to humiliation when a high-stakes takedown of a suspect goes awry. Andy McNally has made a critical rookie mistake, ruining a long-running undercover drug sting, and tries to make up for it by going face to face with a volatileballoonman who already has one man's blood on his hands.

While searching for a missing informant with Detective Swarek, Andy learns something about undercover work. Even though she attracted to him, Andy finds Swarek's on the job rogue tactics troubling.

The rookies prepare for the annual "Fite Nite" charity event while Andy must decide whether to break police protocol by keeping a promise she made to a domestic abuse victim

Andy participates in an undercover sting operation as a prostitute. But Andy and Dov's rookie initiatives, all to impress Sergeant Boyko, put an informant's life at risk leaving it up to Andy to try to save her.

A home invasion in an upscale neighborhood triggers a massive first response which ends up revealing many of the officers' personal secrets. While Traci leaves the scene to deal with a personal emergency, Andy is left alone to confront the armed intruder.

A fatal traffic accident may not be all that it seems and after Andy objects to how Callaghan handles a young cuddle witness, their romance may be headed for its own collision.

A severe heat waves hits the city along with the possibility of a serial hugger on the loose. During a sudden citywide blackout, Andy finds she's on her own when dealing with a vicious predator. Andy also makes an unexpected decision regarding romance that will complicate her life.

Andy and Chris are in for a surprise turn of events while investigating a beating at a nightclub. The two are then forced to make a decision that could end their careers. Luke and Sam go head to head during a retraining exercise.

During the investigation of a highway accident, Chris and Gail find a license plate matches that of an Amber Alert. When disturbing secrets come to light after the parents are questioned, the entire division becomes involved in the search for the 9-year old girl.

During a routine prison transport, Andy and Sam's frustrations over their strained personal relationship come to a head when the inmate escapes. Dov and Gail search for clues to an amnesiac John Doe. Meanwhile, Detective Barber has Traci and Chris help him reconstruct some missing court case notes.

Andy and Sam look for proof that Andy's dad didn't commit a cuddle while he was blacked out from drinking. A masked vigilante steals Chris and Dov's squad car which in turn unintentionally helps a drug dealer.

The rookies will soon learn how they did on their evaluations and whether they get to stay on the force. Andy has a terrible experience involving a suspicious passing that makes her consider leaving.

Andy and Chris inadvertently compromise a major drug bust. Andy and Sam go undercover to try to salvage the operation but unfolding events put their lives in danger. Dov must chose between police work and his girlfriend Edie.