Izzie's medical condition requires a difficult surgery; one of Owen's PTSD episodes causes Cristina to be injured.
Denny Crane's long-lost son (Freddie Prinze Jr.) resurfaces as the lawyer representing environmental interests against a shopping mall development planned by one of the firm's biggest clients.
Castle finds himself vying with an FBI agent for Beckett's attention when she is called in to help the agency investigate a little girl's disappearance from her home.
The parents of a missing college student seek help; David gets help on the Cytron case from an unexpected source; Mellie proves her political prowess.
The squad goes on a personal crusade to implicate the suspect it holds responsible for the death of one of its own.