The interns, now residents, deal with their own crops of interns. Callie struggles with her new position, and Burke makes a decision.

Lexie persists in trying to get to know Meredith, and Mama Burke descends once more.

Meredith reluctantly helps Lexie with her first surgical procedure, while Lexie helps keep George's `repeater' status a secret from their fellow interns.

Meredith and her intern lose a patient after they give her the wrong diagnosis, Callie confronts Izzie, and McDreamy bonds with the other Grey.

Meredith feels she's being haunted by her Mother's ashes, and Cristina is denied a surgery for a surprising reason.

A man survives a parachute accident without serious injury, two women refuse treatment because of a wedding contest, and Cristina and Izzie jockey for inclusion in Hahn's surgeries.

Hahn bans Cristina from her service, Bailey covers more and more of Torres' duties, and Izzie and George go to extreme lengths to recapture the magic of their first encounter.

Miranda begins her first day as chief resident vowing to put a stop to personal dramas spilling over into the workplace, but when her old high school crush turns up in ER, she finds her tough stance weakened. Elsewhere, a coach crash fills the hospital with students, and Thatcher Grey puts in an appearance.

Bailey's professionalism is tested as she battles to save an injured paramedic with a shocking secret. Meanwhile, Ava appears at Seattle Grace, and Lexie bonds with a patient.

Meredith furiously works to save the life of a paramedic trapped in an ambulance; Lexie holds a patient's life in her hands; Derek must rely on a nurse's help to save a patient; Bailey struggles to balance her personal life with work.

Bailey's family faces a medical trauma just as her marriage falls apart. George's mother makes a surprise visit. A faith healer challenges Erica and Alex's belief in traditional medicine. Derek must deal with the aftermath of his kiss with Rose.

Six weeks after Derek and Meredith ended their relationship, Meredith, Alex, Izzie and Cristina compete in a surgical contest, with Bailey serving as judge; George and Lexie adjust to their new, squalid apartment; Callie finds a friend in Erica.

Addison returns to Seattle Grace to perform an operation and is surprised by all the changes in the lives of her former co-workers. Derek and Meredith's clinical trial has its first patient. Rebecca returns with shocking news for Alex.

The new clinical trial patient has a secret, Yang is dealt a blow from a distance by Burke, the nurses refuse to work with Sloan, and Meredith's therapist tells her some home truths.

Cristina is still in her slump and turning mean, Izzie finally confronts Ava/Rebecca, and Meredith's anger with her therapist is challenged by a patient with a Cinderella story.

A surgical team battles the clock as they try to save a boy encased in cement, Karev's situation with an ever-disintegrating Ava brings back painful memories that interfere with his judgment, Derek and Meredith have one last chance at their clinical trial.

Meredith and Derek are at odds over whether or not to continue with their 13th clinical trial patient and the doctors lift the final critical pieces of cement from the young boy's body. Meanwhile, Alex rushes Ava into the hospital and is forced to confront the reality of her condition.