The Boston Police Department is on high alert during the city's July 4th celebrations.

After yearlong tensions between rival gangs culminate in back-to-back retaliation shootings in a single night, Detective Tim Stanton leads an investigation involving both the Gang and Fugitive units to end the battles once and for all.

Officer Jenn Penton reunites with her troubled twin sister after her stay in drug rehab.

Detectives Tim Stanton and Rich Medina are determined to uncover the truth in a mutilation case that has scared the victim into silence.

Gunshots at a party set off an intense pursuit for Officer Terrique Chambers and the Gang Unit.

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.