[ Warning: The following contains spoilers for Wednesday's episode of The 100. Read at your own risk!]

The 100 took a detour into the past this week with a backdoor pilot for a potential prequel spin-off series. In the episode, we got a ton of answers about how the Grounder civilization actually began, but we also got some clues about where the final season of The 100 is headed.

Upon meeting Cadogan (John Pyper-Ferguson), aka The Shepherd, Clarke's (Eliza Taylor) first question was obviously how in the hell he escaped earth and made it to a whole new galaxy hundreds of years later. The episode then flashed back to the night the bombs went off, 97 years before The 100 pilot episode. 

The story centered on Calle (Iola Evans), Cadogan's daughter and former Second Dawn cult member. Though she, her mother, brother, and father made it into the Second Dawn bunker, Callie was never content to live like that forever. With some help from Becca (Erica Cerra), she turned a group of defectors into Nightbloods and led them to surface. She even became the first Flamekeeper when Cadogan had Becca burned at the stake.  

TV Guide spoke to showrunner Jason Rothenberg about this sneak peek at his potential spin-off as well as what he has planned should it get picked up to series by The CW.

Discover Your New Favorite Show: Watch This Now!

How much of this prequel did you already have figured out when you introduced Becca and the Second Dawn, and how much of it came together later when you were tying it into this season?
Jason Rothenberg: Here's what we had way back when; I knew that the forbearers of the Grounders came from a Second Dawn, for the most part, and so that's as much as we had. Why the bunker was empty when the door was first opened when our heroes founded in Season 4, I believe, was an unanswered question that I felt was the hole really that needed answering and so that sort of combined with this idea at the beginning of the season that I wanted to answer any kind of unanswered questions that were out there still... This was a story, by the way, that we were going to tell. Before I decided to do the prequel, I had developed a different project as a prequel. We were going to do this and tell the story this season regardless, and it just so happened to dovetail nicely with a potential second part of the franchise. We know that lots of things are happening at this time in our mythology. Also, I have a plan, in theory, to get back to space where Becca just came down after they blew up her space station on Unity Day. So we know that the Ark is coming together in space, right? So somewhere in Season 1, possibly the beginning of Season 2, of the new show, I would get us back to space where we would meet great, great grandpappy — Blake and Clarke's great, great grandparents. So you'd still not need to know anything about the protagonists of our show to go for that ride when we do introduce those characters, but it would certainly be fun for fans of the original... It's funny Richard Harmon and Sachin [Sahel] both have pitched that they look exactly like they're great, great grandparents. So yeah, who knows? I love them both.

Iola Evans, <em>The 100</em>Iola Evans, The 100

How much of The 100 do you actually hope to incorporate into the spin-off given that this is a prequel and our favorite characters can't really ever pop in? Would it be mainly Easter eggs?
Rothenburg: I think the Easter eggs are more historical than anything else. To use a weird metaphor, we've tasted the fruit, and now we're planting the seeds. The idea of where the Grounder language came from, the idea of Becca and how Callie becomes the first Flamekeeper - like all of these stories, the 100-years-later versions of these stories were told, and now we're sort of getting to the history. I think [it's] cool because you don't have to know what happened afterward to go for the ride this time. You don't need to be a fan of the original to watch the show and go for this ride. I think it'll bring, ideally, of course, new fans to the original once they did start to take this story in. That's if we get picked up...I feel like we need help, you know. We need help from you and we need help from the fans and at this point I won't say it's a long shot, but I definitely feel like it'll have to take a groundswell from from you guys to get us orders at this point because it's getting late.

Here's Everything we Know about The 100 Prequel Spin-Off

I also want to talk about Callie and Reese's (Adain Bradley) brother-sister dynamic because it's very different from say, Octavia and Bellamy's relationship. Where does that sort of very deep love, but also intense competition come from for them?
Rothenberg
: This is a story that we would tell in the series because I do plan on using flashbacks to the pre-apocalypse time quite often. And so, we will see the way [Cadogan] parented them, which was very, very, almost militaristically, preparing them for the end of the world that he saw coming, that he believed was coming, and ultimately, obviously, was proven right. He trained them to be fighters. He trained them to be survivors, and it left a lot of wounds for sure. Callie was always his favorite. Callie was more like him probably than she would care to admit. She was very good with languages and codes and ultimately, once he found that space ball, that she calls it, probably put her to work helping him figure out what it was. Reese was more of the sort of physical type, not quite as inclined as his sister was in the areas that made their father proud. And so he was craving that approval always... It's referred to in the episode but what ended up happening was Callie and Reese were training, Reese was taking it easy on his sister, dad got in and said, "Take me on, big guy, tough guy." And ultimately in a sort of jujitsu match with his son, because he refused to tap out, ultimately broke his son's arm, which was the last straw for Mom. Mom left, Callie went with mom because she had enough and wanted a real life and wanted to sort of experience the world and participate in the protest movements in the street that were building around the group called the Trikru, by the way. And brother surprisingly stayed with father, despite that. So when our story begins, we see them now in those camps, right? Obviously, as bombs fall, mom and sister are brought back into the fold. I just pitched a whole story that's not part of the episode.

Are we going to find out what happened to Reese and Callie's mom should the series get picked up? 
Rothenberg:
Absolutely. Crystal Balint, who plays Grace, is such a good actress - amazingly natural, really talented. And we'll definitely be sort of telling the story of "She's out there. She's got a hazmat suit on. She doesn't have Nightblood. She's got a finite amount of oxygen. She's looking for her daughter. Her daughter doesn't know she's out there. Her son is looking for his sister in order to get that Flame back. Will they be able to get mom in time to give her the Nightblood and save her or not?" That'll definitely be an early Season 1 story, for sure.

Iola Evans and Adain Bradley, <em>The 100</em>Iola Evans and Adain Bradley, The 100

Cadogan obviously thinks Clarke has the Flame, and he thinks that Callie is in there. Is that just a guess that he's made?
Rothenberg: We know that from Octavia's memories in M-Cap, they saw quite a lot of this show. But clearly they did not see the part of the show where the Flame came out of Clarke. They saw when it went in, but not when it came out. So they believe she still has it in her head. Clearly, we know she doesn't. And if and when they find out that she doesn't, then they'll lose whatever leverage they have. But until then, they have some leverage, which hopefully, we'll see if she can use that to get her friends rounded up and taken back home to Sanctum. That's the plan anyway, but of course, on The 100, plans don't usually go the way that they're designed.

The 100: The Second Dawn Cult Explained

Becca claims that she saw Judgment Day when she activated that Anomaly Stone on Earth. So what, if anything, can you say about what she experienced in that moment?
Rothenberg: It's important, I'll put it that way. What she saw is definitely what Cadogan has based his whole sort of post-that-moment theology around. This whole idea of a last war, which could be the thing that allows the human race to finally transcend to whatever the next level of humanity is. And that's what sort of driven him, literally to almost obsession, to uncover and discover. He feels like because he has the Flame, which he knows would contain the mind of Becca, and Becca knew what the code was that she entered and turned that starlight on — if he can get that code, then he can start that war. His goal is to save the human race. I mean, it is ultimately altruistic. He does want to do it for all of us. But it has, like I said, become an obsession. And he's pretty much willing to do whatever it takes to get that accomplished. I think it's safe to say that we are setting up for that eventuality.

Clarke has really been through the wringer, losing her mom and Bellamy in a matter of days, so where is she at mentally and emotionally right now?
Rothenberg: She's pretty broken. I mean, her whole drive this season was to not lose anyone else. And here she does find out and at the end of [Episode 7] she just lost her best friend, and it devastates her. We'll definitely see the toll that takes on on all of them. Obviously, we've seen already how it's destroying Echo (Tasya Teles). We'll see it affecting Octavia (Marie Avgeropoulos). Some people have been surprised by [Octavia's] reaction, but she's now much different than the girl that we last saw, remember. She's older, she's spent 10 years being a mother to Hope... So she's kind of Zen Octavia now, but it is obviously devastating for her as well because Bellamy was her brother, who she loved more than anyone. Anyway, we'll see it affect all of them going forward.

The 100 Season 7 airs Wednesdays at 8/7c on The CW.

Eliza Taylor and Lindsey Morgan, <em>The 100</em>Eliza Taylor and Lindsey Morgan, The 100