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…

As Derek begins his role as interim chief, he faces a potential lawsuit when Bailey and Meredith’s patient awakens from anesthesia mid-surgery. Meanwhile, Teddy refuses to place Cristina on her…

After learning of Richard’s drinking problem, Derek confronts him for the sake of his friend and the hospital, Izzie returns, hoping to reconcile with Alex, and tensions run high between…

Mark flies Addison to Seattle to help with a difficult procedure on his pregnant daughter, Sloan, Owen questions Teddy’s motives when she assigns Cristina the lead on a complicated 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 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…

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…

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…

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…

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…

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…

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…

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,…

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….