All New Grey’s Anatomy Tonight : 5.04 “Brave New World”

(Copyright 2008 ABC Studios / ERIC McCANDLESS)

Grey’s Anatomy is all-new tonight with its fourth episode of the fifth season, “Brave New World.”

Here’s what we know about tonight’s episode:

• Derek will be completely naked! Oh, fine, he’ll have a pillow covering the McBits, but close enough…
• Guest stars include: Amy Aquino (Marianne), Larry Brandenburg (Arnie), Bre Blair (Lauren), John Sloan (David), Steven W. Bailey (Joe), Kathleen Early (Dr. Daisy Pepman), and Max Burkholder (Duncan).
• Callie and Erica plan their first date and Callie is nervous
• Cristina discovers a new section of the hospital that none of them had seen before
• Derek finds one of Mer’s mom’s diaries and Meredith freaks

If you missed the promo for the show, I’m adding one that’s slightly better quality than the one I posted before. Find it after the jump!