GREY'S ANATOMY - "I Will Follow You into the Dark" - The Chief and Meredith try to convince a depressed Derek to come back to work, on "Grey's Anatomy," THURSDAY, MARCH 12 (9:00-10:02 p.m., ET) on the ABC Television Network. (ABC/RON TOM) ELLEN POMPEO, JAMES PICKENS JR., PATRICK DEMPSEY