Barnes goes on a dangerous undercover mission involving an ambitious gang leader who is plotting turf wars and massacres across the Bronx in a bid for more power.

The team searches for a young woman who is heading down a deadly path of vengeance, using ties to an online radical conspiracy organization to further her cause. Also, Barnes must make a life-changing decision, finding it hard to not let the dark side of her job affect her.

When a young man accidentally shoots a cop in self-defense and goes on the run, the team members find themselves in a moral dilemma on the best way to carry out justice. Also, Barnes and her wife struggle with their plans to have another child.

The team heads to D.C. to protect Ortiz's former informant after a hitman tries to kill her. Also, Sarah helps Jess' family prepares for Byron and Marie's last-minute wedding on Jess' farm.

The team attempts to hunt down a family annihilator before he continues his murder spree. Also, Barnes’ intrusive mother puts pressure on her marriage.

While holiday shopping, Barnes and Jess are caught in the middle of a mall shooting, with the exits rigged so no one can escape. Also, Gaines, Hana and Ortiz try to help from the outside, knowing their team's family members are inside and at risk.

The team is thrown for a loop when they discover the abductor of a disgraced state police detective is connected to someone from a recent case.