Molly Kidder

Bailey and Seattle Grace's new pediatric surgeon try to save the life of a longtime patient; the admission of a death row inmate angers Derek; Izzie tells Alex that she has been seeing Denny.

Bailey leads a team of doctors performing a string of surgeries in which each procedure depends on the one that preceded it; Derek gets all the credit for the brain tumor study he did with Meredith; Lexie tries hard to get George to notice her.

Derek and Addison face off as they try to save a pregnant patient's life; a surgeon botches a standard procedure; Bailey is shocked by the chief's recommendation letter.

Derek decides to quit after learning that more of his patients have died than survived; Izzie's interns make an unsettling discovery about "Patient X."

Derek's mother makes a surprise visit and meets Meredith for the first time; Mark tries to hide his relationship with Lexie; Cristina and Owen try to go on their first date.

Izzie's medical condition requires a difficult surgery; one of Owen's PTSD episodes causes Cristina to be injured.