Frank struggles after Joe Hill's lineage as a Reagan is revealed; Erin and Anthony receive gift-wrapped evidence; Danny's opposition to authority clashes with Jamie's adherence to the rules, as both brothers work to solve a murder.

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.

After Danny witnesses a drive-by shooting, he butts head with the detective assigned to the case; a childhood friend of Jamie's is convinced that she has single-handedly solved a cold case murder.

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.

Jamie and Eddie experience marital tension when Eddie allows her newly released ex-convict father to live with them; Danny and Baez go out of their way to help a desperate man find his missing sister.

Frank enlists the help of an old friend, Sloane Thompson, to investigate a cyber-attack on the NYPD that forces Danny and Baez to release an evasive suspect. Also, Baez questions her place within the NYPD; Eddie is torn over a workplace dilemma; and Jamie wrestles with a family secret.

Frank is at odds with his friend Archbishop Kearns when he says the NYPD arrested the wrong man for a murder; Eddie tries to get justice for a sexual assault survivor; Jamie and his nephew, Joe Hill, butt heads over fair police practices.

Eddie's former partner returns and brings an accusation of excessive force against an officer; Danny and Baez clash with a troubled foster child at the center of their latest investigation; Erin must make a tough decision about her campaign.