Danny and Jamie combine forces to convict a notorious drug lord, as Erin nervously awaits the Governor's selection for the new District Attorney. Also, Frank and his grandson, Joe Hill (Will Hochman), face a difficult decision as they navigate their new and complicated family ties.

The Reagans confront hard choices on the job when Frank deals with a police captain who's losing his grip over his precinct, and Danny faces backlash from the Baez and Internal Affairs over a tough call he made in the field.

Erin tries not to feel overpowered as her new boss shadows her at work just as she's trying to get a nervous eye-witness to reveal the identity of who shot her boyfriend. Also, the serial killer who previously held Danny and Baez hostage resurfaces, and when Jaime arrests an intrusive reporter who appears at a series of store lootings, it leads to a standoff between Frank and the Attorney General over the press' First Amendment rights.

Baez confides in Danny and asks for his help in proving her innocence after she finds a corpse in her front yard. Also, Erin struggles to find a peaceful solution when she receives harsh case notes from her boss, Jamie and Eddie butt heads over the handling of a young cop’s punishment, and Frank makes his whole team attend therapy after Gormley exhibits troubling behavior.

Frank takes matters into his own hands to save Gormley's career when complaints against him become public knowledge; Danny and Baez learn to be allies when the transgender community comes under attack.

Danny consults a psychic to solve the murder of a young boy; Frank is at odds with the mayor over how best to protect the city from an uptick in crime following a high-profile shooting; Erin investigates a decades-old case.

Frank causes family tension when he assigns Jamie to guard Danny after a hit is put on him; Frank tries to stop his grandson from seeking revenge after he’s attacked; Eddie gets a hostile new partner.

Danny and Baez's attempts to find who assaulted a shop owner are hindered by the community's refusal to cooperate; Erin's suspicions about her boss rise; Gormley, Garrett and Baker are threatened by a new staff member.

Jamie and Joe search for an undocumented teenage girl who has been sex-trafficked; a woman in witness protection is murdered; Frank calls out the district attorney's office for instituting a new rule that classifies armed robbery as a misdemeanor.

Danny and Baez investigate a series of violent robberies targeting luxury timepieces; Erin is conflicted about criminally charging a potentially innocent man; Frank is forced to reopen a case in which the officer involved was acquitted.

Danny and Baez’s investigation into the death of a chess hustler is complicated by interference from the victim’s son; Jamie tries to make amends with a man he regrets putting away as a young officer.