Season three brings us to Boston's high society Beacon Hill. Following his dismissal from the FBI, Jackie Rohr lands a lavish new gig running security for a wealthy family. Life is good until secrets begin to unravel. When an investigation opens – implicating local and federal authorities – assistant district attorney Decourcy Ward sees an opportunity to finally rip out the machinery perpetuating a broken system.

Season two centers on a federal housing project in the Roxbury neighborhood of Boston that is plagued with drug violence and a rightful distrust in local law enforcement. As coalition leader Grace Campbell (Pernell Walker) works tirelessly on behalf of the community, her efforts are undermined by gang activity happening right under her nose. Enter irreverent FBI agent Jackie Rohr (Bacon), who is here to exploit Boston's defective criminal justice system in a desperate attempt to salvage his own career. Unfortunately for Jackie, assistant district attorney Decourcy Ward (Hodge) is onto his adversary's latest misstep. In time, the personal antagonism between these two escalates to an all-out war between the offices of the U.S. Attorney and the Suffolk DA. No one is safe from the collateral damage.

When idealistic assistant district attorney Decourcy Ward arrives in Boston, he discovers a place rife with violent criminals emboldened by local law enforcement agencies in which corruption and racism are the norm. Ward forms an unlikely alliance with corrupt-yet-venerated FBI veteran Jackie Rohr, and together they take on a family of armored car robbers from Charlestown in a case that grows to involve, and ultimately subvert, the city's entire criminal justice system.