The Walking Dead season 4, episode 2 “Infected” aired Sunday night on AMC, and the pigs saved the day at the prison.

Last week’s premiere episode of The Walking Dead season 4 – watched by over 20 million people in the first four days – ended with evidence of a scary new infection that sweeps over a human quickly for no apparent reason. It was new character Patrick who fell ill quickly and for a reason that will be plaguing the humans throughout the season as they try to learn what’s causing it.

The opening scene depicted Tyreese and his girlfriend Karen enjoying some tender moments with kisses and song, and on the way back to her cell block Karen is followed by recently-turned character Patrick who we see is thirsty for some human. He almost goes into Karen’s cell but then hears a noise in a neighboring unit and eats the man within.

Now with the sun up, Patrick continues to eat the man (who’s now a zombie himself) when he hears a noise somewhere else. The presence of the zombies within cell block D is realized moments later just as Michonne was heading out on a hunt. As she re-enters the compound she’s attacked by a couple of zombies that bring her to the ground.

Rick and company head into cell block D where they find Patrick and others on the attack. Carol finds one person who’s arm she’s ready to amputate to save him, but she realizes it’s no good because the zombie also bit the back of the man’s neck. Carol brings the turned man’s daughters into his cell for a few final words with him. She tells the kids she needs to put a knife through his head, and the elder (but still young) daughter offers to do it herself. She can’t muster up the strength however, and Carol does the deed.

Trying to figure out what caused the infection, Hershel, Daryl, Carol, and Rick among others think it may be because of a type of flu. They suspect Karen may have it as well because she’s coughing so they decide to isolate her.

The day doesn’t improve for the survivors. At the outer fence a group of zombies are piled against a particular area, and it looks as if they’re close to pushing the fence down with their collective weight. One reason they’re all in one spot? It looks like someone was feeding them rats. Rick and Daryl head outside the fences and put pigs – who Rick cuts – around the grounds to keep the zombies occupied. When cutting one of the pigs, the blood splatters Rick’s face.

In a small scene, Michonne was asked by Beth to hold baby Judy, and after resisting she begins crying with the baby in her arms. A sign that she once had a child or wants one badly herself?

Later, Carol and Carl speak about the knife lessons being taught by the former, and she believes she’s right to do it because they need to be able to fend for themselves. She asks Carl to simply not bring it up to his father so he doesn’t have to lie. Despite this request, he decides to tell his father who doesn’t voice his opinion on it but says he won’t stop her. He also decides to give his son a gun.

The episode ends with another infection, this time in the sickly Karen. Her man Tyreese was delivering her some flowers when he sees she’s missing. Following the trail of blood, he finds her and another body burned to a crisp outside.

What did you think of tonight’s new ‘Walking Dead’?

While we wait for next week, watch the episode’s teaser trailer in which we see Tyreese livid about the passing of his lady:

The Walking Dead season 4, episode 3 titled “Isolation” airs Sunday, October 27 at 9 p.m. eastern/pacific on AMC.