While undergoing aggressive cancer treatment, Izzie focuses on planning Meredith and Derek's wedding; Callie's father visits; Owen seeks help with his PTSD.
All reassess their personal lives after witnessing a chance reunion between two long-lost lovers in the emergency room; Karev treats a troubled teen (Demi Lovato); Meredith shares her suspicions with Cristina.
The team pursues a serial killer in Milwaukee, with three fewer members since Hotch asked to be transferred, Prentiss quit, and Gideon is missing.
Michael's medical condition forces him to go to the hospital; Lincoln and Sucre get into an explosive situation; Agent Self meets with a shocking ally.
Bonnie and Christy try to ensure that everything goes smoothly when Violet finds a couple to adopt her baby.