It's a cop's worst nightmare. After a drunken car accident, Detective Salinger's gun is stolen by gang members in a dangerous neighborhood. When Gang Squad Detectives Nate Moretta and Sammy Bryant arrive on the scene to help out their boss, Moretta reluctantly agrees to assist Bryant in the search for the perpetrators and Salinger's weapon without calling it in. Launching an off-the-books manhunt to retrieve the weapon, they make a disturbing discovery – that the gangs are no longer afraid of the police; a local gang is using assault weapons, bullet-proof vests and military tactics to become a powerful urban street army – ready to declare war. Elsewhere, still preoccupied with her personal life, Detective Lydia Adams is caught off guard when a man exposes himself to her outside her home.