Lowery is assigned to watch over a smart-mouthed group of female gang members, called the Latin Queens, when one of them is found dead in her apartment. Suspects are brought in where Kersey interrogates them and discovers that one of the gang members is a cop who had been working undercover for over two years to bring down the gang. Meanwhile, MacElwaine arrests a man who throws Hector over a bar and injures the man's ribs while doing so. They take him to hospital where a doctor is amazed at the injuries he has received. Also, the precinct prepares for a new era as Officer MacElwaine announces that he is going to retire after 25 years on the force, and Santoro is promoted to Lieutenant. Although, everyone in the precinct accepts MacEwaine's decision to retire, his ability to defuse a hostage crisis later that day gives him confidence that he may still have a few more good years on the force. Jonas throws a double-party for the entire precinct to celebrate Santoro's promotion and ...