When AMC released a new poster for The Walking Dead earlier this month, the Season 4 plot description that came with it teased a mysterious threat to the group from inside prison walls. Today, the network released an extended behind-the-scenes featurette that offers more questions than answers. For example, executive producer Denise M. Huth reveals that this threat within the prison is neither a zombie nor a human. Could it be ghosts then? Werewolves? We do get some concrete information from showrunner/executive producer Scott M. Gimple, who revealed that the season premiere, "30 Days Without an Accident", takes place six or seven months after Season 3 ended. We also see Carl (Chandler Riggs) interacting with some kids his own age, Carol (Melissa Suzanne McBride) teaching the youngsters how to handle a knife, and much, much more.