Issues surface when Derek's estranged sister, Amelia, visits unexpectedly; Meredith and Derek continue to try to ease Cristina back into surgery.
After a burn victim unexpectedly dies in the ER, the Chief and board member Jennings question the residents, as all the staff members defend their actions in an effort to save their jobs.
The hospital is hit with an unprecedented crisis; Meredith and Cristina's surgical skills are put to the test.
Owen puts the residents through a rigorous trauma certification drill; Cristina is left alone to monitor an ill lung transplant patient.
Amelia arrives at Seattle Grace to beg Derek to help with the gliosarcoma case; Cristina and Owen have heated arguments during marriage counseling; Alex realizes he needs to improve his people skills in order to be a good doctor.
