Ready or not, here it comes. In just one short week, Grey's Anatomy will kick off its first full season without Patrick Dempsey, whose character, Dr. Derek "McDreamy" Shepherd, died toward the end of Season 11. The show must go on, of course, but as leading lady and surgeon extraordinaire Meredith Grey (Ellen Pompeo) says in the first teaser for Season 12 — released by ABC on Thursday, Sept. 17 — "everything has changed."

Indeed, Meredith's life appears to have been turned upside down in the months since her husband's death. In one brief scene from the 20-second trailer, she runs down a hallway littered with toys to find one of her new roommates smashing a hole in the wall with a sledgehammer.

Another scene shows her half-sister Maggie (Kelly McCreary) landing a mean right-hook — square in the face of an unidentified blonde woman at the hospital.

The show — not to mention Grey Sloan Memorial Hospital — already looks different without Dempsey. But that's not necessarily a bad thing. As Pompeo told Entertainment Weekly recently, it's called Grey's Anatomy for a reason.

"It's like, Annalise Keating carries the show, Olivia Pope carries the show," she said, referring to Viola Davis and Kerry Washington's characters on How to Get Away With Murder and Scandal, respectively. "But somehow, Meredith Grey needs someone. Why can't I just be the lead of the show the way Annalise and Olivia can? Why can't I be on that poster by myself?"

Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics, and more delivered straight to your inbox!