The police department is on high alert during Boston's Fourth of July celebrations.

After tensions between rival gangs culminate in back-to-back retaliation shootings, Detective Tim Stanton leads an investigation to end the violence.

Officer Jenn Penton reunites with her troubled twin sister; the Fugitive Unit responds to a call about an officer shooting.

Detectives Tim Stanton and Rich Medina are determined to uncover the truth in a mutilation case that has scared the victim into silence. Off duty, Officer Jenn Penton steps into the boxing ring for the first time to fight for a cause close to her heart.

Gunshots at a party set off an intense pursuit for Officer Terrique Chambers and the Gang Unit. While off-duty, Chambers plans a large event to raise money for the organization that has helped his autistic son make remarkable strides.

Devoted husband, father and Gang Unit Officer Greg Dankers works relentlessly to offer justice to a victim. Meanwhile, a fellow officer decides it’s time to prepare a surprise proposal to his girlfriend.