Derek Shepard lies on the bed, naked and waiting for Meredith Grey.  When she arrives she playfully engages in conversation about his day.  She sees a diary on the bedstand and assumes it's Derek's commenting that she never knew he kept a diary.  When he tells her that it's her mother's diary she becomes a little concerned.  He explains that he found it in a closet while he was looking for room to put his stuff away.  Suddenly she needs to take a shower after helping Crisitina move to her new apartment.  She takes the diary and retreats for a calming shower before rejoining him.

At work, she's freaking out to Cristina Yang.  "Why is he digging around in my house, bringing up my mother's ghost?"  "Because you invited him," is Cristina's matter-of-fact answer.  Bailey assigns Meredith to cardio with Erica Hahn and sends Cristina to work in the clinic.  While Cristina complains that she'll be "putting bandaids on people who don't have the balls to get real injuries," she tells Meredith to watch herself because Hahn is scary.  

Meredith will be assisting Hahn on a heart surgery for a young boy and has to read up on some things to prepare.  She checks with Cristina frequently to pick her brain for ways she can practice.  Cristina's most exciting case is just a rash.  She tries to get Sloan to upgrade it to surgery, but he tells her there's no chance and sends her to the Dermatology for some cream.  Cristina walks into the Dermatology department and soon finds herself in a whole new world.  A world where they put fruit into the water, and the residents and interns get frequent massages to keep them relaxed.  A world where they leave work to get facials and worry about keeping lotion on their skin.  It's like the day-spa of doctors.  She is totally hooked and decides to park herself on the couch in their office to relax.  When Meredith joins her, she joins in the awe of this alternate universe they've found.  Meredith has told Erica Hahn that she's done this before, so she turns to her best friend for help.   She stays while Cristina teaches her the techniques she'll need for the surgery.  "It's like watching a living freak show," she says and soon Izzie Stevens has joined them.

Finally, a sensible George O'Malley comes looking for them and tells them all they have to get back to work, and it's time for Meredith's surgery.   When Cristina gets back to the clinic, her rash patient is in distress and can't breathe.  Lexie Grey is trying to fix it, but didn't know what to do.  Cristina quickly moves the patient into the E.R. and finds the medication she needs to stabilize the patient.  Turning the patient over to Miranda Bailey, she offers to do the biopsy of the skin that is necessary for further testing.  Bailey asks if she's taking an interest in derm.  Cristina assures her she's not.

In Meredith's surgery, things are going well.  Hahn watches her closely as she performs the procedure.  Even though things went smoothly, Erica tells her, "Cristina is a better teacher than a colleague, I see . . . Lie to me again and the next heart surgery you'll ever see is yours when I cut your heart out with a steak knife."  I think that says it pretty clearly, don't you?

Cristina admits to Meredith that her derm patient was fun for a minute, but then it was over.  Dermatology is not for her, she prefers the excitement of surgery.

Back home, Meredith and Derek are trying to work out the living situtation.  He says that maybe he should move back to his trailer.  She refuses and says, "I want you here." She then suggests that Derek should move his stuff into her mother's den.  When asked if she's sure, she continues to assure him that he needs to have his own space there.  He tells her that she needs a place, too, a place to go when she need to be alone.  Meredith says she can always go to Cristina's apartment, but Derek has a better idea.  We soon see Meredith and Cristina opening up the diary of her dead mother, reading it aloud in Derek's trailer.  Outside on the door the sign reads, "Dermatology."