The mystery of Izzie's strange behavior is unwittingly solved 由 her interns, as Derek falls into a dark depression and quits, ON ABC'S "GREY'S ANATOMY".
AS IZZIE GOES THROUGH AGGRESSIVE CANCER TREATMENT, SHE THROWS HERSELF INTO PLANNING MEREDITH AND DEREK'S WEDDING, AND CALLIE GETS A VISIT FROM HER DISAPPROVING FATHER, ON ABC'S "GREY'S ANATOMY"