Credit: Video Still

Grey's Anatomy Season 9, Episode 12: "Walking on a Dream" (January 24) is going to introduce a new face to the hospital: Dr. Cahill (Constance Zimmer). She's here to make things run more efficiently, and the docs are not a fan.

In this sneak peek of the episode, Derek (Patrick Dempsey) runs up against Dr. Cahill, and he seems surprised to find she's not shaken by his confidence and brusk demeanor. We have a feeling she'll be more than a match for our favorite surgeons.

Credit: Video Still Photo: Preview Clip of Season 9, Episode 12 Sneak Peek: Derek vs. Dr. Cahill (VIDEO)

For more Grey’s spoilers, click here.

Catch the episode tonight, January 24, 2013, at 9 p.m. ET/PT on ABC.

Rebecca Martin is an editor at Wetpaint Entertainment. Follow her on Twitter @BeccaDMartin.