Izzie and Cristina are assigned a close-to-brain-dead John Doe who may be a viable candidate for organ donation, and helpful to George's patient, who needs a new liver. Meanwhile, Meredith and Alex butt heads over a patient of their own.

Alex uses Izzie's modeling against her, and her last ad causes a patient to reject her care. Meredith finds parallels between a patient and her mother, and Christina must deal with a hospital-savvy patient.

Meredith is horrified when her mother is admitted, and everyone is concerned when Cristina collapses in the operating room. Meanwhile, Addison is determined to save a very sick baby.

Cristina is determined to get back to work, and despite not being fully recovered, she manages to crack an odd case. Meanwhile, Addison offers to help Bailey with a complicated surgery, and Alex receives important news.

Izzie returns to the hospital, but finds it difficult to go inside, and George is tired of Callie's presence at home. Meanwhile, Addison cannot seem to get rid of Mark, and Cristina tries to cope with caring for Burke.

Meredith becomes a patient, and Derek and Addison are equally angry at Richard for allowing Mark to join the staff. Meanwhile, Izzie receives a visit from Denny's father, and Burke is plagued by doubt over his ability to return to surgery.

Callie hides in her office, frustrating Bailey who's itching to teach someone. Elsewhere, age becomes the theme as Izzie tries to convince 'Really Old Guy' he shouldn't die, Webber and Sloan set out to prove they're not too old to learn a new technique, and Karev is saddled with an intern who's past his prime.

Meredith and her intern lose a patient after they give her the wrong diagnosis, Callie confronts Izzie, and McDreamy bonds with the other Grey.

There is a huge problem affecting the whole hospital including patients too. Richard is trying to do his best to solve the problem.

Calllie worries over her first real date with Erica. Cristina stumbles upon a neglected area of the hospital.

As hospital personnel jockey for notice to keep from being fired, Izzie returns to surgery early and Bailey's triple aneurysm patient refuses her procedure because of her schizophrenic son.

Thatcher is hospitalized with liver failure, and Meredith fights anger and guilt while deciding her responsibility. Sloan treats an octogenarian who wants an implant. Izzie's interference in Hunt's cancer case may have deadly consequences.

When Derek receives an unexpected and unwelcome visit from his estranged sister, Amelia, issues between the siblings -- both past and present -- come to the surface; the Chief tries to help Alex when he notices that he's refusing to use the elevators after his near-fatal shooting; and Meredith and Derek continue their efforts to ease Cristina back into surgery after her post-traumatic stress.

Things are hostile on all fronts when a visit to the obstetrician results in some disturbing news for Meredith and Derek and Lexie loses it when she notices Meredith and April getting closer. Meanwhile, a car crash brings in multiple traumas and Jackson tries using his physical attributes to get ahead in the operating room, while Cristina's self-doubt carries outside of the hospital and into her house-hunting with Owen.

The chief makes a decision that shocks everyone at Seattle Grace.

A stampede at a comic book convention leads to an influx of patients.

The survivors of the crash are presented with a settlement offer, forcing them to choose between putting the incident behind them or investigating the true cause. Meanwhile, Jackson and April struggle to work with each other, Bailey is annoyed by the new attendings' behaviors, Callie struggles to communicate with Arizona, and Cristina learns to work with her new colleagues in Minnesota.

As Cristina begins to make new "friends" in Minnesota, Meredith struggles with whether or not to tell Derek about an extremely rare case she is working on. Meanwhile, Arizona begins work with her new prosthetist and tensions flare around work when Jackson's mother comes into town.

Derek and Meredith adjust to life at home with their newborn.

The doctors put together a fundraising gala.

Owen introduces Callie to the Veterans Hospital patients in hopes that she will help them with her robotic limb lab, Jo becomes jealous of Alex and Meredith's friendship, and Maggie continues to confide in Richard. Meanwhile, Alex and Bailey prepare to go in front of the board.

Secrets from Ellis Grey's past come to light when Meredith watches old videos and reads through her mother's journals. Meanwhile, Maggie rocks the hospital with an unexpected announcement; Alex gets new responsibilities and Callie focuses her attention on the Veterans' project.

When Maggie gets an invitation to her ex-boyfriend's wedding, she starts to reevaluate her choices.

Owen suggests the interns learn about breaking bad news to patients' families.

A family argues at the hospital following a car crash at a funeral; Arizona is caught between Alex and Andrew; Ben has a new parenting role; Amelia helps Meredith and Maggie work through a problem.

Alex realizes the clinic doesn't make him less of a doctor while Meredith struggles with professionalism with Riggs

Harper Avery arrives at Grey Sloan, putting Bailey on edge. A familiar face from Meredith's past returns as a patient, and Amelia tries to manage a secret.

Amelia confronts a difficult situation; Meredith deals with the fallout from her conversation with Nathan; Maggie finds herself at an awkward family dinner; Jackson receives big news; Richard and Bailey search for the stars of tomorrow.

Meredith works on a patient who happens to specialize in matchmaking, and a seemingly drunk patient pushes Richard's buttons and gives him a medical mystery to solve. Meanwhile, Maggie tries to reach Teddy after bearing the burden of her secret becomes overwhelming as she struggles with issues in her own personal life.

Meredith turns heads when she shows up to work done up and ready for her blind date later that day, while Alex makes a questionable decision in order to save a patient. Meanwhile, the burden of knowing Teddy's secret keeps Maggie up at night, ultimately making her decide she has to tell someone.