Boston Blue is peeling back the emotional layers behind Danny Reagan’s departure from New York 
and at the heart of the move is deeply personal family drama.
CBS’s upcoming Blue Bloods offshoot reveals that Danny’s decision to leave NYC is directly tied to his youngest son, Sean Reagan. Actor Mika Amonsen known for The Republic of Sarah, Hudson & Rex, and the 2023 slasher Thanksgiving has been cast as Sean in the new series, stepping into a role previously played by Andrew Terraciano throughout all 14 seasons of Blue Bloods.
In Boston Blue, Sean has relocated to Boston to begin a new chapter of his own, joining the Boston Police Department as a patrolman. That career move becomes the emotional catalyst for Danny’s own life altering choice. Rather than remaining in New York, Danny chooses to stay close to his son, setting the stage for a renewed father and son relationship.
According to the official character description, Sean is determined to honor the Reagan family legacy but on his own terms. Joining a police department outside his hometown allows him to step out of his family’s shadow, while Danny’s presence in Boston gives them a chance to reconnect in ways they never could before. The series positions their relationship as one of its emotional cores, built on reconciliation, growth, and shared sacrifice.
Boston Blue expands the Blue Bloods universe by introducing a new, influential law enforcement family alongside the Reagans. Sonequa Martin Green stars as Detective Lena Silver, Danny’s new partner and the eldest daughter of a prominent Boston policing family. Gloria Reuben plays Mae Silver, the family matriarch and Boston’s District Attorney. Ernie Hudson appears as Reverend Peters, Lena’s grandfather and a respected pastor at a historic Boston Baptist church.
The ensemble also includes Maggie Lawson as Sarah Silver, the strong willed and decisive Boston PD superintendent and Lena’s stepsister as well as Marcus Scribner as Jonah, the family’s rookie cop brother.
Described as a “universe expansion” of Blue Bloods, Boston Blue follows Danny Reagan as he takes a position with the Boston Police Department, navigating a new city, a new department, and a very different family dynamic. While the setting may have changed, the heart of the franchise remains intact: family, legacy, and the difficult choices that bind them together.
Airing Fridays at 10/9c this fall, Boston Blue promises to explore not just why Danny left New York but what it costs to choose family over familiarity.