Justice runs in the family.

Danny and Baez grapple with a homicide investigation brought to their attention by Maggie, the medium who previously helped them solve a case; Frank looks for a way to help his ex-partner Lenny Ross when Lenny's daughter gets arrested. Frank and Erin are at odds when Frank learns the district attorney's office keeps a list of officers they consider unreliable; Danny and Baez recruit a retired mobster to assist in an investigation; a predator poses as a ride-share driver. Frank's esteem for an old friend proves to be a mistake; Jamie asks Erin for help apprehending a perp who shot at him after learning she chose not to send him to prison six months ago; Eddie clashes with her new boss. Franks takes one of Jamie's cases to heart when it involves the suspicious death of his friend's wife; Erin receives an unsolved robbery case that proves to be impossible to crack without help from Anthony. The Reagans have discovered their newest family member, NYPD officer Joe Hill (Will Hochman), son of deceased officer Joe Reagan, who was killed in the line of duty. As the first family of the NYPD continues to overcome the day-to-day challenges that always come their way, they do so while confronting the reality of a changed world. Also, Erin (Bridget Moynahan) is disappointed that she was passed over as the District Attorney of New York and must get used to working with her new boss Kimberly Crawford (Roslyn Ruff) and Jamie (Will Estes) and Eddie (Vanessa Ray) continue to balance their work and personal lives working in the same precinct. Frank (Tom Selleck) continues to help his newfound grandson withthe pressures of being a Reagan and uncovers new information about his father's (Len Cariou) past. City Council Speaker Regina Thomas battles with Frank over protest against police brutality.