"The Walking Dead" season 4 episode 4 titled "Indifference" will air on AMC at 9pm ET on Nov. 3, 2013.

The official synopsis for "The Walking Dead" season 4 episodes 4 is as follows:

"The supply mission faces hurdles; the situation at the prison worsens."

Two new characters, Jack and Erin, will be introduced in tonight's episode. The two new characters are set to replace Karen and David who were killed off in the show.

In a promo video for episode 4, Lizzie tells Carol, "A lot of people are going to die, it always happens."

In last week's episode, Hershel warned that they could be facing an outbreak as more and more prisoners became infected with the flu.

Lizzie was escorted to the sick ward by Carol and finally the killer was revealed as Carol herself when Rick confronted her. "Did you kill Karen and David?" he asked Carol. She replied, "Yes."

If you miss the episode on November 3, be sure to watch "The Walking Dead" season 4 episode 4 online via live stream on the AMC website.

"The Walking Dead" is an American horror drama television series developed by Frank Darabont based on the comic book series by Robert Kirkman, Tony Moore, and Charlie Adlard.

Watch a sneak peek preview video of "The Walking Dead" season 4 episode 4 below: