Faces old and new collided at Seattle Grace last night as Derek's mother Carolyn Shepherd (Tyne Daly) made quite an impression, while serial killer William (Eric Stoltz) caused friction between Meredith and Derek apart, Dr. Arizona Robbins (Jessica Capshaw) feuded with Bailey, and Izzie sort of dumped ghost Denny (Jeffrey Dean Morgan).

That's the short version, of course, and the long one is much better. Follow the link for a full recap of last night's Grey's Anatomy, "Sympathy For the Devil."

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