The interns and residents treat victims of an apartment complex explosion as Alex looks into the cause of the devastating accident. Mama Burke arrives at Seattle Grace to pick up the rest of Burke's personal things while Cristina trades wedding gifts for surgeries. Meanwhile, Lexie tries to talk to Meredith, who is less than willing to do so; Callie deals with the stress of being Chief Resident; and Bailey tries to figure out what to do with her excess leadership skills.