The Walking Dead: World Beyond gang found that out on Sunday’s episode when they holed up in a former high school to seek both shelter and supplies.

MATT NEGRETE: Yeah, there's a bit of a backstory we laid in there for episode four about the high school and a lot of the student body that was there when things went bad.

And we see the yearbook that Iris has, and she has a little bit of envy towards what seemed like maybe a secular life that she never got to experience, this high school life, and so that starts off the story.

So we know that there was this artsy girl named Sabina, and there are some characteristics that she shares with Iris, and one of them is, she's very artsy and that's something that Iris has always been attracted to.

I don't know if I want to give the whole thing away, but we know that some of the students from the high school end up holing up in this fallout shelter that was in the basement and that things went bad.

There are a lot of canned goods that are still present when Hope and Huck come across the shelter towards the end of the episode, but it looked like maybe the person with the backpack who had some issues and was missing a leg didn't quite make it out, so maybe that was the person that had a plan to maybe take things and run.

Now, when you say that you don't want to give away everything that you guys wrote, does that mean that this may come back into play even though it seems like our characters have moved on away from the school — that this bomb shelter mystery may unfold a little more.

And episode 4 was designed to be a little bit more of an intimate episode where we were really focusing on the characters, but almost in the context of this "haunted house." So it really was about them holing up in this spooky environment that's fairly contained, in which they'd have to break up and they each have their own missions and they each come across different things.

And even Iris in a way, it's almost like she's haunted by this past she never had.

Speaking of ghosts, tell me about having some of these old high school scenes come to life, one right at the beginning and one later as iris and Silas are dancing.

It's not necessarily Iris getting a flashback episode, like we've seen in the past.

But for Iris, it's about seeing things through her specific lens.

And we started the pilot with a dream sequence in which it was partially animated, so there's a world in which that's how she sees things through this lens that's very artistic, and that's ultimately the thing we wanted to capture, especially in an episode in which she's thinking about all the things that she's given up to live for the future, to try to be everything for everyone, and one of those things is her art?

But I guess what we really don't know is, are we seeing his dad in that moment that he was killed.

So it's really a great emotional episode and I'm looking forward to everybody checking that out.

We don't know where we are, but it's a new character, this woman who seems to be doing something very interesting with some empties, that seems very scientific based.