The characters established in a two-part NCIS intro last season are back, including Zoe McLellan as Northern outsider Meredith Brody, currently seeking a place to call home - as Pride informs her, "Where you lay your head in this city defines you" - and Lucas Black (Sling Blade) providing some local flavor as Christopher LaSalle, boasting an authentic drawl and apparent street smarts. The case of the week, which begins when a body part is found in a crate of crawfish, gives Bakula a chance to express some earnest emotion, when the victim turns out to be a young sailor he mentored after rescuing him from the local gang scene. Many CBS dramas tend to reinforce a status-quo comfort level - ergo, three hours of NCIS goodness over two nights - but Person of Interest has always been different, a more provocative and unpredictable thrill ride, and that hasn't changed as the show enters its fourth season (10/9c) blowing up its already unnerving world of constant paranoia and danger. Much of the fun in the premiere is discovering how each of the vigilantes are hiding in plain sight - "Mayhem Twins" Shaw (Sarah Shahi) and Reese (Jim Caviezel), the playfully berserk Root (Amy Acker), and everyone's moral compass, Finch (Michael Emerson) - taking on new jobs and identities to elude Samaritan's eternal sinister surveillance. Person of Interest's mix of brainy sci-fi conspiracy and outrageous carnage is as intoxicating and entertaining as ever. [...] following the premiere of the American Masters special The Boomer List (9/8c, check tvguide.com listings), PBS will pay homage to one of the all-time comedy greats with a late addition to the lineup, the revealing 2010 documentary profile Joan Rivers: A Piece of Work (10:30/9:30c, check tvguide.com listings).