The show has a superb new villain in John Lithgow's Trinity Killer; Lithgow has played bad before, but he's not copycatting his earlier scoundrels. He uses eerie calm, even when murdering, to give you chills. Also welcome: Keith Carradine's sly FBI profiler, guaranteed to keep Trinity, Dexter, and former girlfriend Deb all on their toes.
''Wanna know a secret? Daddy kills people,'' was Dexter's heart-slicing line to his newborn in the premiere. For the rest of us, that just makes Dexter more heartwarming. A–