Grey's Anatomy ABC Premieres: Thursday, Sept. 25 What to Expect: When we last saw Meredith (Ellen Pompeo) and Derek (Patrick Dempsey), they seemed to be headed toward a happily ever after. But come on -- we all know there will be some fresh challenges to their star-crossed relationship this season. The season premiere will also feature "Journeyman" star Kevin McKidd as a military doctor who sparks Cristina's (Sandra Oh) interest and the Chief (James Pickens Jr.) dealing with the fallout of Seattle Grace no longer being ranked among the best teaching hospitals. Creator Shonda Rhimes has also promised a "really great story" for Katherine Heigl's Izzie. Given the sturm und drang involving Heigl and the show's writers earlier in the year, read into that what you will.