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.After being named interim chief, Derek [...]

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 [...]

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.Source: ABC

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.Source: ABC

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.

The parents of Arizona’s 10-year-old patient offer the hospital a generous donation, but Arizona finds herself in a conflict of interest when the patient’s condition worsens. Cristina tests her boundaries with Owen.

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 the holidays come and go, Miranda has a surprise visit from her father, William, who has a strong disapproval of her choices in life. Mark and Lexie must cope with a person who re-enters Mark’s life, and Thatcher Grey questions the Chief’s behavior, but Meredith is quick to come to the Chief’s 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.