Grey's Anatomy [OmU]

As Meredith and Cristina discuss their relationship woes at the Emerald City Bar, their session of lamenting is interrupted when Joe, the bartender, collapses. And as Chief Webber recovers from brain surgery, he appoints one surgeon as interim chief - much to the dismay of another surgeon -- and he assigns George to report back with hospital gossip.

When a family arrives at Seattle Grace Hospital after a serious car accident, Alex learns that their injuries are only the beginning of their problems. Meanwhile, as Dr. Webber recovers from brain surgery, it seems that his wife has some concerns about the state of their marriage.

Some very deep secrets are made painfully public when Meredith's mother, who suffers from Alzheimer's disease, is brought to Seattle Grace for a surgical procedure. Meanwhile, some frightening news about Cristina's health is brought out into the open.

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

Meredith and Dr. Shepherd have to use more than medicine when a young woman's traditionalist, religious father forbids her to have a life-saving operation. Meanwhile, George and Alex are forced to perform surgery under less than ideal conditions in an attempt to save a patient's life, and its decision time for Derek and the two women in his life.

As Meredith nervously awaits a final decision from Derek, her angst is interrupted when a train crash brings several seriously injured patients to the hospital, including Bonnie and Tom, a pair of passengers who've been impaled on a metal pole. And Addison Shepherd sees great potential in Izzie, who must decide whether her loyalty as Meredith's friend outweighs professional gain.

Cristina, Izzie and Meredith aggressively pursue the case of Shane, a male patient who seems to have a hysterical pregnancy, which fascinates them and the entire medical staff; and a sheltered young patient inspires Alex to better express his feelings for Izzie.

Derek and Addison Shepherd's professional relationship is challenged when their closest friends come to Seattle Grace seeking a radical, preemptive operation to avoid breast and ovarian cancer.

The Thanksgiving holiday is more difficult for the interns and residents than any of them is willing to admit, as Izzie plans a big dinner at Meredith's -- but it remains to be seen who among the invited guests will actually show up.

Meredith is mortified when her "one night stand" shows up at the hospital suffering from priapism and needing medical attention; a woman carrying quintuplets is overwhelmed by numerous medical issues as she navigates her high-risk pregnancy; and Alex's shortcomings frustrate Izzie.

Cristina Yang has little sympathy for Constance Ferguson, a prison inmate who jeopardizes her health just to get out of solitary confinement. Meanwhile the interns all keep careful watch on the family of premature quintuplets with a variety of serious health challenges, Izzie's anger at Alex reaches boiling point, and Dr. Addison Shepherd decides to teach Izzie a very painful lesson.

A young boy needs a heart transplant but doesn't seem to want it, and his treatment causes Burke and Yang to have philosophical differences. Meanwhile, when the interns rally to help Alex prepare to re-take his exam, Meredith has to remind Izzie of the true spirit of the Christmas holiday; and despite the reconciliation with his wife, Derek isn't in a festive mood.

Izzie seems to be getting over Alex when she shares an undeniable chemistry with Denny Duquette, a patient who's awaiting a heart transplant, and George treats Bex, a young teen hermaphrodite.

The truth is in short supply as Meredith and Cristina lie to each other about the status of their relationships. George is given the unpleasant task of discharging an elderly patient who's no longer sick, but refuses to leave the hospital; and Alex learns his fate after re-taking his medical exams.

The nurses at Seattle Grace Hospital go on strike, leaving the doctors to fend for themselves; Meredith's mistake in treating an elderly patient is brought to light by the patient's friends and Izzie treats a pregnant teen.

Meredith's fears that she is in for a bad day are realized when a medical case arrives at Seattle Grace that threatens the lives of everyone in the O.R.

Despite the best efforts of the Seattle Grace staff, the code black situation escalates.

Someone from Derek and Addison's past arrives in Seattle and shakes things up. Meanwhile, Burke learns about Christina's secret and, after a visit with her mother, Meredith looks into more of her family's dirty laundry.

Meredith and George suddenly find themselves at odds at work. Meanwhile Bailey, although technically still on maternity leave, finds herself treating Addison for an unusual feminine issue, and Alex finds himself oddly jealous when Izzie pays more attention to Denny.

It becomes a bad day for Cristina when Bailey instructs her to take care of her baby. Meanwhile, Derek and Addison come to terms with their relationship, and Denny continues to be an obstacle in Alex's getting closer to Izzie.

When a series of deaths occur at Seattle Grace, the uncanny events bring out the doctors' superstitious sides and make Izzie nervous about Dennys surgery. Meanwhile, Derek and Addison discuss making a more permanent living arrangement, and Richard treats a very special, old friend.

George begins to overstay his welcome at Burke's apartment; Meredith learns a secret about her father; Bailey worries her colleagues will not treat her the same now that she's a mother and Alex gets a lesson in bedside manners.

Izzie grills George about the personal details of his life, Addison takes Alex to task about a sensitive case, and Burke feels the pressure when he treats his musical hero.

The interns deal with a family involved in a car accident, Derek lets his emotions get the best of him, and Burke and Izzie make a new suggestion to Denny.

Finn gives a health update on Doc, Meredith is assigned to work with Callie for the day while George gets paired with Derek, and Burke and Izzie continue to try to find a heart for Denny, on part one of the season finale.