Brooke Blanchard

As Meredith nervously awaits a final decision from Derek, her angst is interrupted when a train crash brings several seriously injured patients to the hospital, including Bonnie and Tom, a pair of passengers who've been impaled on a metal pole. And Addison Shepherd sees great potential in Izzie, who must decide whether her loyalty as Meredith's friend outweighs professional gain.

Cristina Yang has little sympathy for Constance Ferguson (special guest star Rosanna Arquette), a prison inmate who jeopardizes her health just to get out of solitary confinement. Meanwhile the interns all keep careful watch on the family of premature quintuplets with a variety of serious health challenges, Izzie's anger at Alex reaches boiling point, and Dr. Addison Shepherd decides to teach Izzie a very painful lesson.

Someone from Derek and Addison's past arrives in Seattle and shakes things up. Meanwhile, Burke learns about Christina's secret and, after a visit with her mother, Meredith looks into more of her family's dirty laundry.

Cristina meets Burke's parents -- and in the most awkward of circumstances -- the interns campaign for Izzie's reinstatement to the surgical intern program, Addison takes a break from her hospital duties, and a surgical patient lives what may be her last day to the fullest.

When a series of deaths occur at Seattle Grace, the uncanny events bring out the doctors' superstitious sides and make Izzie nervous about Denny's surgery. Meanwhile, Derek and Addison discuss making a more permanent living arrangement, and Richard treats a very special, old friend.