Candice Afia

Cristina, back from her honeymoon trip, searches in vain for Burke; Meredith, Cristina, Izzie and Alex spend their first day as residents with their own groups of interns.

An ambulance crash endangers the lives of the paramedics involved; Bailey treats a patient who refuses her help; Ava returns for Alex and meets his other girlfriend.

Cristina and Burke's wedding day arrives - along with the interns' first exam results - and a successor to the Chief is named, as Callie and George make a big decision about their relationship.

Derek decides to quit after learning that more of his patients have died than survived; Izzie's interns make an unsettling discovery about "Patient X."

Everyone in the hospital tries to find a new organ donor for a patient; Mark is left in a compromising position; Cristina tries to avoid Owen.

Izzie's medical condition requires a difficult surgery; one of Owen's PTSD episodes causes Cristina to be injured.