A freak ice storm brings trauma patients to Seattle Grace; Meredith and Derek discover that "happily ever after" isn't easy; a mysterious military doctor catches Cristina's eye.
A freak ice storm brings trauma patients to Seattle Grace; Meredith and Derek discover that "happily ever after" isn't easy; a mysterious military doctor catches Cristina's eye.
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.
Derek finds an old diary of Meredith's mother; Callie anxiously prepares for her first real date with Erica; Cristina stumbles into a part of the hospital that she and the other residents have never seen.
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.
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.
The residents compete for a solo surgery; Derek asks Bailey for advice when he feels Cristina is interfering in his relationship with Meredith; Erica discovers a surprising connection between a surgical resident and a longtime patient.
Sadie, one of Meredith's oldest friends, becomes an intern at Seattle Grace; Lexie leads her fellow interns in unorthodox, secretive surgical training; a new surgeon brings rules and order to the OR.
Meredith, Bailey and Cristina help Lexie and Sadie when a routine surgery goes awry; Derek and Owen treat a man who got injured while sleepwalking; Mark comforts the sleepwalker's daughter.
Cristina is awarded the first solo surgery among the residents, but she is forced to give it up and choose her replacement; Lexie is impressed when Mark performs a cutting-edge procedure; Callie doesn't know if Sadie is friendly or flirtatious.
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.
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.
Everyone in the hospital tries to find a new organ donor for a patient; Mark is left in a compromising position; Cristina tries to avoid Owen.
Derek looks for the perfect way to propose to Meredith; Lexie wants Mark to go public with their relationship; Bailey considers taking her medical career in a new direction.
Addison, Naomi and Sam rush Archer to Seattle Grace, where they reunite with old friends in hope of saving his life; Izzie devises a medical game to teach the interns; Owen runs into someone significant from his past.
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."
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.
While undergoing aggressive cancer treatment, Izzie focuses on planning Meredith and Derek's wedding; Callie's father visits; Owen seeks help with his PTSD.
Izzie's mother (Sharon Lawrence) pays her a surprise visit; Thatcher tries to make amends with Meredith and Lexie; Meredith and the Chief argue over a controversial case.
Derek and Meredith get ready for their wedding; college students injured in a car accident are admitted to the ER; Izzie starts experiencing familiar symptoms.
Izzie ponders whether to have a risky procedure; a patient prompts Owen to reassess his place at Seattle Grace; George has stunning news for Bailey; the doctors of Seattle Grace band together to save the victim of a traffic accident.
Izzie ponders whether to have a risky procedure; a patient prompts Owen to reassess his place at Seattle Grace; George has stunning news for Bailey; the doctors of Seattle Grace band together to save the victim of a traffic accident.