As Cristina tries to recover, she proves to be a very difficult patient, and a visit from her mother doesn't improve her demeanor any. And Meredith's mother, Dr. Ellis Grey, has the hospital staff running in circles.

All the nurses at Seattle Grace Hospital go on strike, leaving the doctors to fend for themselves. George refuses to cross the picket line and finally joins the nurses on their strike while Alex, Cristina, Izzie and Meredith meets Bailey's stand-in: Dr. Cindy Aaron, the complete opposite of Miranda Bailey. Izzie agrees to work on a difficult pregnancy case with Addison, while Cristina and Alex are in the pit attending to a young married woman with a real bad case of rash. Meredith happens on an old woman that she needs to intubate and then learns she was DNR.

Derek learns one of Addison's secrets. Bailey talks about motherhood and depression to a mother who is set to have cancer surgery and who seems to not care about any decisions concerning the future. A resident is fiercely questioned about the death of a male patient. An ex-couple meet before lunch and get stuck - Meredith and Addison work on their case. Things get awkward when the ex-couple's daughter, Michelle, arrives at the hospital.

Time has passed but not much has changed. Sexual angst still runs rampant in the halls of Seattle Grace. Derek and Rose have been dating and Meredith has noticed the activities of her current off-again ex-boyfriend. The doctor's are in the midst of a competition.

After his fellow surgeons try and fail to bring Derek back to work, Meredith must summon the strength to convince him. Meanwhile the hospital is abuzz as Mark attempts a rare face transplant surgery. Cristina, at last awarded her first solo surgery, is more focused on the needs of her friends, and Izzie does her best to keep her medical condition a secret.

In his new role as Chief, Derek restores the hospital lecture series, and Richard, Bailey and Callie present to the group pivotal surgical cases from their pasts Bailey reflects on her first days as a shy resident, Callie looks back on a polio case, and Richard recalls a case in which he and Ellis worked on a patient diagnosed with GRID, a virus later called AIDS.

An elderly patient admitted into the E.R. for a heart condition sees a familiar face, a long lost love who happens to be in the E.R. as well for a fractured arm, and the staff find themselves caught up in their love story. Meanwhile, Karev treats a troubled teenage patient (guest star Demi Lovato) whose parents brought her in for schizophrenia, and Meredith can't help but tell Cristina about her suspicions of Owen -- which inevitably messes with Cristina's head.

The residents are on their own with the dreaded night shifts while the attendings go out to play to celebrate Derek's grant for his clinical trial.

Personal and work pressures are adding up and have Meredith visibly on edge, Owen conducts formal interviews for the Chief Resident position, Cristina grows increasingly defiant, Alex and Lucy's undefined relationship gets tested, and Jackson suddenly backs out of the Webber's diabetes trial.

The doctors split into teams for a risky surgery involving conjoined twins; Bailey recruits Meredith to be a buffer between her and Ben when he puts pressure on moving their relationship to a more serious level; Richard teaches Alex a tough lesson in the OR; meanwhile Teddy questions Cristina about what exactly happened to Henry during his surgery.

The survivors from the crash are asked to make an almost impossible decision that will affect the rest of their lives. Meanwhile, tension grows between Jackson and April after they're forced to work together, and Alex tries to restrain himself with one of the interns.

The discord and chaos created by the hospital's new management team causes one physician to question his future at Seattle Grace. Meanwhile, the doctors and the interns must juggle several transplant surgeries at once, each coming with its own set of obstacles.

The hospital gets inundated with flu infected patients, which causes the doctors to slowly fall ill one by one. Derek must fight off the sickness as he prepares to give a speech on brain mapping and the residents place bets on who will fall ill first. Meanwhile, a new doctor at the hospital gives Alex a glimpse into an alternate form of medical practice.

The doctors work frantically to save a young boy who was accidentally shot. Meanwhile, Arizona is upset when Callie tries to make an important decision about Sofia’s future without consulting her

Richard and the attendings set out to make Eliza’s first day at Grey Sloan a bumpy one. Meanwhile, Meredith tries to track down Alex.

A young boy is admitted to Grey Sloan Memorial and his case has a profound impact on the doctors. Meanwhile, April is faced with a surprising patient, and Jo continues to deal with her estranged husband.

Meredith breaks a hospital record; the doctors are sent scrambling in the wake of a massive overdose within the community; Jackson wants to take Maggie camping; Levi and Nico's relationship continues to develop.

Meredith heads up a pro bono surgery day, but the overwhelming patient response causes her to struggle to keep things in order. DeLuca treats a teenage patient whom he suspects is in danger and desperately tries to get Bailey to support his theory.

Bailey panics as she hears there has been a surge of COVID-19 cases, knowing she has loved ones in an assisted living facility. Meanwhile, Jackson and Richard team up against Catherine to teach her a lesson, and Teddy continues to try to mend her frayed relationships. After an intense surgery, Jo is uncertain about her future.

Bailey is on edge when an accreditation council stops by Grey Sloan to review the residency program, while Richard sets an assessment of his own for the same day. Meanwhile, Nick returns to Seattle to perform a first-of-its-kind operation with Meredith.