Bailey and a team of surgeons must remove a young girl's inoperable tumor; as the new head of trauma, Owen Hunt challenges the surgical abilities of the residents and the attending doctor's methods.
Meredith tries to convince Derek to come back to work; Mark attempts a face transplant surgery; Izzie tries to keep her medical condition a secret.
Izzie's medical condition requires a difficult surgery; one of Owen's PTSD episodes causes Cristina to be injured.
The nurses' complaints about Mark Sloan's trysts result in a date-and-tell policy; Cristina is forced to face her feelings for Burke; Meredith and Derek admit a veteran into their clinical trial.
A plumbing leak becomes a flood, causing chaos at Seattle Grace; the chief tries to implement new teaching policies; George tries to take his residency exam again; Derek hopes to move Meredith's roommates out of her house.