
Grey's Anatomy
Thursdays 9:00 PM on ABCWatch Grey's Anatomy Season 6 Online
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In part two of the two-hour season finale, Cristina and Meredith's surgical skills are put to the ultimate test, and the game changes for all the characters.

In part one of the two-hour season finale, Seattle Grace Hospital is hit with a crisis like no other in its history. Guest star Mandy Moore plays Mary, a patient of Bailey's.

In "Shiny Happy People", an elderly patient admitted into the E.R. for a heart condition sees a familiar face. Karev treats a troubled teenage patient, Hayley (guest star Demi Lovato). Meredith tells Cristina her suspicions regarding Owen. Read our full recap below!

In "How Insensitive", Bailey preps the team with mandatory sensitivity training. Derek comes face to face with a former patient's husband in a wrongful death deposition. Old wounds are opened for Yang. Read our full recap to see what happened!

Sloane returns to Mark's apartment, just as she's going into labor. Meanwhile Teddy sees Derek's invitation to illustrious cardiothoracic surgeon Tom Evans' as a threat to her future employment at the hospital, and the team work on a crab boat captain who has been stabbed with a giant shark hook. Read our full recap to find out what happened!

In "Sympathy for the Parents", Alex's younger brother, Aaron, shows up at Seattle Grace-Mercy West with a hernia, it's up to Alex to get Bailey's approval for his pro bono surgery. Matters are further complicated when Aaron discloses that his family has not heard from Alex since he arrived in Seattle, and parts of Alex's past long kept secret are revealed to his friends and fellow doctors. Read our full recap to find out what happened!

In "Suicide is Painless", Teddy's patient seeks to end treatment and her life, turning to Hunt for help. The situation triggers Hunt's memories of his life at war and his past relationship with Teddy.

A patient needs an extremely difficult surgery and Richard and Owen vie for it, leaving Derek in a difficult bind yet again. Bailey nervously prepares for another date with Ben.

Dr. Harper Avery is rushed to Seattle Grace-Mercy West, and the staff is surprised to discover that one of their own is related to this medical legend, whose requests flummox Derek and Richard.

A flashback episode sheds light on the affair between the Chief and Ellis in 1982. Separate 2004 sequences show Bailey in pre-"Nazi" days and Callie before she was introduced.

The doctors treat dozens of people when the roof of a romantic restaurant collapses on Valentine's Day; Meredith struggles with her new duties as the chief's wife.

Derek begins his role as interim chief. Teddy refuses to place Cristina on her service. Arizona tests Alex out in pediatrics. Mark refuses to speak to Lexie.

Derek confronts Richard for the sake of his friend and the hospital. Izzie returns, hoping to reconcile with Alex. Tensions run high between Teddy, Cristina and Owen.

Desperate to help his pregnant daughter, Mark follows Addison to Oceanside. Derek's suspicions are raised when the Chief recruits Meredith to assist with a high profile operation.

Thanksgiving, Christmas and New Year's pass. Miranda is visited by her father. Mark and Lexie cope with the arrival of a woman from his past. Thatcher questions the Chief's behavior.

Izzie returns to Seattle Grace with an important figure from her past. Stress takes a toll on Richard. Owen recruits a fellow Iraq war vet as the a cardiothoracic surgeon.

All eyes are on Arizona to help a patient with an enormous donation to spare. Cristina tries to test Owen's boundaries, and Alex is losing it over Izzie.

Derek must help the most unlikeliest of all; the hospital lab-tech, Isaac, when it turns out that he has an inoperable tumor surrounding his spine. McDreamy also questions Richard's authority.

A burn victim's death in a chaotic ER prompts the Chief and the board to find who is responsible, as all the Mercy West and Seattle Grace residents scramble to save their jobs.

Newly-merged Seattle Grace and Mercy West residents vie for surgeries and their careers, while Arizona stands by Callie when her father employs a priest to convince her to date men, and Izzie experiences the brunt of her new competition.

When Meredith and Lexie Grey's father, Thatcher, returns to the hospital with a failed liver, it's up to Meredith to save his life. That won't be easy for myriad reasons.

Izzie returns to work after a near-death experience. An announcement from the Chief has residents expecting layoffs and scrambling to survive the cuts.

The doctors of Seattle Grace continue to battle their own demons and cope with the loss of George in their own way, while a couple of patients make a big impact on the doctors, too.

The Season 6 premiere of Grey's Anatomy kicks off on a somber note as Dr. George O'Malley is laid to rest and the Seattle Grace doctors are profoundly impacted in their own ways.