Be prepared for lots of changes in this weekend's TV shows. "Grey's Anatomy," "Blue Bloods" and "Upstairs Downstairs" are all about moving forward, "Person of Interest" gets closer to resolving its mystery, and there are far-reaching consequences on "Boardwalk Empire." Moving on The plane crash changed everything on "Grey's Anatomy."

Thursday's episode flashes back to the site of the crash and lets viewers watch as each doctor tries to cope with the heartache and injuries it caused.

Back at Seattle Grace Hospital, everyone is still struggling to find some normalcy in the middle of the chaos. The series airs at 8 p.m. Thursday on ABC, channel 8.

Emmy Award-winner Margo Martindale ("Justified") guest stars as a woman from Root's past.

Nick (David Giuntoli) asks Hank (Russell Hornsby) for help to keep Monroe safe, and Hank uses this time to get caught up with his knowledge of the "Wesen world." Also, an old European acquaintance pays Captain Renard (Sasha Roiz) a visit.

FYI: Claire Coffee has been promoted to series regular. She plays Adalind, a Hexenbiest and Nick's enemy.

Turns out she is involved in a secret relationship with a high-powered councilman who just happens to be a friend of Frank's. Richard Burgi ("Desperate Housewives") guest stars as Councilman Mancini.

Mickey makes a decision that has far-reaching consequences when he overrules Eli on a routing call. Margaret (Kelly Macdonald) meets a familiar face while promoting Dr. Mason's classes at the new women's clinic at St. Theresa's.

Back in New York, Lucky (Vincent Piazza) haggles over heroin splits, while in Chicago, Capone's (Stephen Graham) feud with O'Banion (Arron Shiver) heats up when one of his collectors gets roughed up.

Life goes on at 165 Eaton Place with Pritchard taking the rap for Johnnie in a shocking incident, which leads to a revelation that has the staff regarding the butler with disdain. On a diplomatic mission to Germany, Hallam meets Lady Holland's dangerously defiant sister Persie, who has taken a Nazi lover.

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Weekend TV: 'Grey's Anatomy' plane crash changes everything