Season 6

The season follows the journeys of surgical interns, residents, and their capable mentors as they navigate the challenges of the competitive careers they have chosen. Set in the surgical wing of the fictional Seattle Grace Hospital, located in Seattle, Washington, a major storyline focuses on the characters as they adapt to change: the departure of their beloved coworker Stevens following the breakdown of her marriage, O'Malley dies in the season premiere—following his being dragged by a bus, and new cardiothoracic surgeon Teddy Altman is employed at the hospital. Additional threads include Shepherd's promotion to chief of surgery, Seattle Grace Hospital merging with neighboring Mercy West—introducing several new doctors—and several physicians' lives being placed in danger when a grieving deceased patient's husband embarks on a shooting spree at the hospital, seeking revenge for his wife's death.