Where We Left Off: Frank Reagan and his NYPD cop sons Danny and Jamie brought down the Blue Templar, the dirty cops who had killed Frank's other police officer son, Joe.

What's Next: Carrie Underwood and Tony Bennett guest star -- as themselves -- on the season premiere, when they're the performers at a fundraiser Frank and daughter Erin are attending. Meanwhile, Frank gets a new boss, as 'Dexter' star David Ramsey plays new NYC mayor Carter Poole, and Jamie gets involved in a new ongoing mystery, this time involving the mob.

Season 2 premieres Fri., Sept. 23, 10PM ET on CBS