For Blue Bloods fans, Friday night visits with NYPD commissioner Frank Reagan (Tom Selleck) and his family are as much comfort food as the clan's meat-and-potatoes Sunday dinners. In the hit drama's 13th season, expect a slightly more amped-up — but just as satisfying — menu with a serious run for Manhattan DA by Erin Reagan (Bridget Moynahan), a hush-hush position in the PD's Intelligence Unit for Sgt. Jamie Reagan (Will Estes) and some soul-searching by both Det. Danny Reagan (Donnie Wahlberg) and the PC himself.

Like her dad before her in the police department, Erin seeks the city's top prosecutor position to improve the system.

Says Moynahan: "She's unhappy with the direction of the district attorney's office" under current DA Kimberly Crawford (Roslyn Ruff). And she wants to campaign against Crawford's support for booking and then quickly releasing folks Erin considers dangerous. "She understands the police's frustration," the actress says, "but she knows she'll have to thread the needle" and not appear a pawn to either side.

Meanwhile, younger brother Jamie, who traded a legal career for police blues in the first season, has to give up his hard-won sergeant's uniform. He's transferred to the Intelligence Unit when a new captain (Stephanie Kurzuba) insists that, as a married couple, either Jamie or his wife, officer Eddie Janko (Vanessa Ray), must leave her precinct.

Unfortunately for Jamie, his field officer job — extracting intel from incoming perps in exchange for lesser sentences — "is under a cone of silence," says showrunner Kevin Wade. That means no table talk or pillow talk with loved ones.

The hard-nosed, formerly hotheaded Danny has his own ambitions: becoming a better cop by using his mind and his mouth to de-escalate combustible situations instead of a gun. "Given the last few years," Wade says, "the evolving character of a police detective is worth focusing on."