John Prosky

Izzie seems to be getting over Alex when she shares an undeniable chemistry with Denny Duquette, a patient who's awaiting a heart transplant, and George treats Bex, a young teen hermaphrodite.

Violet looks to Sheldon for advice after a patient makes a chilling confession; Addison tries to hide her grief; Cooper and Charlotte adjust to their new life; Sam confronts Sheldon.

A body is found covered in scratches, leading the BAU to believe that the person responsible has a chronic skin disorder.

Dr. House shows special interest in a schizophrenic with deep-vein thrombosis and her teenage son, who is her primary caregiver.

Jack begins closing in on the location where Teri and Kimberly are being held hostage. Meanwhile, Teri and Kimberly create a shock of their own as things get violent at the compound. Also, Senator Palmer's worst fears are realized when he uncovers just how far his campaign backers are willing to go to protect him.

Are there zombies among us? Megan is joined by the new health commissioner in her quest to uncover the truth.