Andy McNally’s first shift on the job turns into mayhem when shots are fired in a downtown rooming house. In the midst of the chaos, Andy triumphantly makes her first big arrest – a suspected drug dealer – who turns out to be Sam Swarek, an undercover officer from her own division. She makes up for her grave mistake by going face to face with a dangerous gunman who already has one man’s blood on his hands.

Andy’s undercover skills are tested – and found to be lacking – during a citywide campaign to clean up the streets, when she’s tapped to pose as a prostitute in order to arrest unsuspecting johns. But the real test comes when Andy and Dov inadvertently put a vulnerable street informant’s life in danger, and it’s up to the two rookies to infiltrate a dangerous gun deal in order to save the trapped woman from a group of ruthless criminals.

After their High School Outreach assignment goes awry, Andy and Chris stumble on the victim of a vicious beating behind a nightclub. When the trail of clues leads them to discover the man’s assailant was a cop, the rookies are faced with a gut-wrenching moral decision – a choice that could dramatically jeopardize their future on the force. Meanwhile, the senior officers compete in a retraining exercise led by Frank Best, the new acting Staff Sergeant.

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.