Title: Undead Again
Air Date: April 30, 2012 at 10:00 PM PDT
When Castle and Beckett investigate the murder of a man with human bite marks on his body, Castle's wild theories start flying. But none are as wild as what their only witness insists happened — a Zombie attack. As the evidence pointing towards an undead assailant piles up, the team plunges into New York's Zombie subculture to find the killer and bring him in — dead, undead or alive.