When Dr Harper Avery, the namesake of the Avery award, is rushed to the hospital, his unusual request for surgery heightens tension between Derek and Richard. The doctors are surprised to learn that Jackson is the medical legend's grandson. Meanwhile, Callie and Arizona help Mark and Teddy move on from their rocky past relationships.

Derek reinstates hospital lectures, leading the doctors to recount stories of their past - Bailey tells of her days as a timid young resident, Callie reflects on a polio case, and Richard recalls an AIDS patient he treated with Ellis.

Valentine's Day hits Seattle Grace with a bang when the roof of a popular romantic restaurant collapses and the doctors have to deal with the fallout. Derek continues to struggle in his new position as his busy shcedule takes its toll, while Meredith faces the pressure of being the chief's wife. Mark and Callie try to convince Sloan to do the right thing for her baby.

Derek faces his first big challenge as interim chief when Meredith and Bailey's patient awakens mid-surgery and the impending lawsuit threatens the hospital. Alex returns to Pediatrics, where he is tested by Arizona, while Teddy refuses to let Cristina on her service. Meanwhile, Mark continues to ignore a heartbroken Lexie.

Derek confronts Richard after learning about his drinking problem, for the sake of his friend and Seattle Grace. Izzie returns, hoping to reconcile with Alex. tensions run high between Teddy, Cristina and Owen in the aftermath of her startling confession.

Addison comes back to Seattle Grace to help Mark's pregnant daughter with a difficult procedure. Meanwhile, Owen questions Teddy's intentions when she assigns Cristina a complicated surgery. While Derek's suspects something is wrong when the Chief assigns Meredith to assist him in a high profile surgery.

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.

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 and delivers shocking news for everyone at the hospital. Richard's responsibilities, post-merger, are taking a toll on him.

A generous 25 million donation is offered to Seattle Grace by the parents of Arizonas 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 Izzies hospital bills to contend with.

When Isaac has an inoperable tumor wrapped around his spine, he wants Derek to do the impossible. Derek tests the Chief's authority when Richard objects to moving forward with the risky surgery.

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.

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.

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.

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.

The hospital staff is left to deal with the aftermath of George's passing. Hitting the staff hard, they all find unique ways to get through the various stages of grief. George's mom returns, faced with the difficult task of deciding what to do with his organs. Everyone is struggling after losing one of their own and are turning to any distraction they can find. Meredith and Derek seem to be consummating their marriage anywhere and everywhere, while Cristina and Owen have been instructed to abstain from sex by Dr. Wyatt.