The Seattle Grace staff has to deal with the aftermath of George’s tragic death. As the news hits the staff hard, they all must find a way to get through the stages of grief. Later, George’s mother arrives at the hospital to decide what to do with his organs.

Though time has passed since George's death, everyone continues to struggle with his passing by finding distractions to keep themselves occupied. Meredith and Derek cope by consummating their marriage anywhere and everywhere, while Dr. Wyatt suggests that Cristina and Owen abstain from sex.

Several weeks after her near-death experience, a recovering Izzie returns to work. Meanwhile, nervous that there will be layoffs in the hospital in the wake of an announcement from the Chief, the Seattle Grace residents compete to survive the cuts, including Cristina, who attempts to work alongside Arizona in pediatrics. And Bailey and Alex’s patient’s already complex case is further complicated by her schizophrenic son.

When Meredith and Lexie’s father, Thatcher, returns to the hospital with a failed liver, it’s up to Meredith to save his life. Meanwhile, Izzie empathizes with a patient riddled with tumors, as Mark, annoyed with Cristina’s competitive zeal, tricks her into assisting on an unusual surgery.

The residents of Seattle Grace and Mercy West vie for surgeries and their careers as day one of the hospital merger begins. Meanwhile, Arizona stands by an enraged Callie when her father, Mr. Torres, employs a priest to help convince her to date men, and Izzie experiences the brunt of her new surgical competition.

After a burn victim unexpectedly dies in the midst of a chaotic ER, the Chief and board member Jennings interrogate the residents to find the culprit, as all the Mercy West and Seattle Grace resident defends their actions in an effort to save their jobs...

When Isaac, the hospital lab tech discovers he has an inoperable tumor wrapped around his spine, he seeks Derek for help. Meanwhile, Richard’s authority is challenged by Derek.

A generous 25 million donation is offered to Seattle Grace by the parents of Arizona’s 10-year-old patient, she finds herself in a conflict of interest when his condition worsens. Cristina tests her boundaries with Owen at the hospital. Alex is left with all of Izzie’s hospital bills to contend with.

Owen recruits Dr. Teddy Altman a former Iraqi veteran, as the new cardiothoracic surgeon, Cristina questions her abilities in the E.R. and relationship with Owen. Izzie returns to Seattle Grace with her high school mentor seeking treatment for his dementia. Richard’s responsibilities, post-merger, are taking a toll on him.

As Thanksgiving, Christmas and New Year’s pass, Miranda gets a visit from her father, William who disapproves of her choices in life. Mark and Lexie cope with an arrival of a woman from his past. Thatcher questions the Chief’s recent behavior as Meredith comes to his defense...

Mark flies Addison to Seattle so that she can help perform a difficult procedure on his pregnant daughter. Meanwhile, Owen begins to question Teddy's motives when she has Cristina be the lead on a complex surgery; and Derek becomes suspicious when the Chief has Meredith assist on a high-profile operation. '

Derek confronts Richard over his alcoholism in an attempt to help his friend and the hospital. Izzie returns to reconcile with Alex, and tensions between Teddy, Cristina and Owen escalate. '

After being named interim chief, Derek begins to settle into his new position but faces a lawsuit when Bailey and Meredith's patient wakes up during surgery. Meanwhile, Teddy refuses to let Cristina be a part of her service, Alex continues to work with Arizona in pediatrics, and Mark avoids talking to Lexie who is still heartbroken over their break up. '

It's Valentine's Day, and the doctors must treat dozens of injured people after the roof collapses at a popular romantic restaurant; Derek tries to manage his busy schedule as Chief of Surgery; Meredith wrestles with her new duties as the Chief's wife; and Mark and Callie team up to convince Sloan to do the right thing for her baby.

Callie, Bailey and Richard present pivotal surgical cases from their pasts when Derek restores the hospital lecture series.

When famous surgeon Dr. Harper Avery is rushed to Seattle Grace-Mercy West, the staff is surprised to discover that one of their own is related to this legend, and his unorthodox request for his surgery causes tensions t between Derek and Richard. Meanwhile Callie and Arizona try to help Teddy and Sloan move on from their pasts and find greener pastures.

A patient arrives at the hospital in need of a complex surgical procedure, and Richard is furious when Derek chooses Owen to do it over him. Meanwhile, Bailey nervously prepares for another date with Ben.

When Teddy's patient seeks to end treatment and her life, she turns to Hunt for help. The situation triggers Hunt's memories of his life at war and his past relationship with Teddy. Meanwhile, Callie and Arizona have a difference in opinion on what their future holds, and Richard tries to adjust to his role as a surgeon.

When Alex's brother shows up at the hospital with a hernia, Alex must get Bailey's approval for pro-bono surgery; parts of Alex's past are revealed to his friends and colleagues.

Sloan returns to Mark's apartment, just as she's going into labor, and Teddy, Mark and the still-fighting Callie and Arizona are there to help with the birth and to get Mark through his grandson's pending adoption. 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

Bailey preps the team with mandatory sensitivity training prior to admitting a 700-pound patient with compounded medical issues, and the case proves to be challenging in every sense of the word. Meanwhile Derek has to come face to face with a former patient's husband in a wrongful death deposition, and spending time with a heart patient's daughter opens up some old wounds for Cristina

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 whose parents brought her in for schizophrenia, and Meredith can't help but tell Cristina about her suspicions of Owen

The hospital is hit with an unprecedented crisis; Meredith and Cristina's surgical skills are put to the test.

In the second hour of the season finale, Cristina and Meredith's surgical skills are put to the ultimate test. This is the second hour of a 2-hour season finale. Two episode entries have been created. The 10pm EST marker will mark to beginning of the second episode.