From director Eli Roth and writer Eric Kripke, and based on the novel by John Bellairs, the family fantasy film The House with a Clock in its Walls follows recently orphaned 10-year-old Lewis Barnavelt (Owen Vaccaro), who goes to live with his rather eccentric Uncle Jonathan (Jack Black) in a creaky old house full of all sorts of magical wonder. As Lewis discovers a hidden world of magic, mystery and the supernatural, and gets to know Jonathan’s best friend and neighbor, Mrs. Zimmerman (Cate Blanchett), he also accidentally awakens the dead, wreaking havoc in his new but otherwise sleepy little town.

During this 1-on-1 phone interview with Collider, screenwriter/producer Eric Kripke talked about getting to turn his favorite kid’s book into a movie, why The House with a Clock in its Walls is so special, how influential this specific story has been on his own writing, throughout the years, how many Supernatural Easter eggs made it into the film, and whether he’d like to keep the Barnavelt adventures going. He also talked about the 2-hour Timeless series finale, which shoots in October and will air on NBC, whether fans will feel satisfied, and if he could see the story continuing, in some form, as well as his upcoming Amazon series The Boys, adapted from the comic books by Garth Ennis, and how it reflects what’s going on in our world today.

Collider: I had so much fun with this movie!

ERIC KRIPKE: Oh, good! Thank you so much. I’m glad you liked it!

When you get to write your favorite kid’s book as a movie, is it basically just a dream project?

KRIPKE: Yeah. It was such a pleasure to write because you feel emotionally invested. People throw this phrase around a lot, but it was truly a labor of love. It really was to the point where it was more than I wanted to write it. I felt like I needed to write it, and I would have been really upset had anyone else written it because it meant so much to me. And it did more than that. It set my career on the path that it went. It’s because of this book, directly, that I wrote Supernatural. So many of the rules from the world of this book, I took into Supernatural. There’s such a direct line between me writing genre, and being a 10-year-old kid and finding this book. It helped me, in so many ways, become the writer that I was. So, to be able to go full circle and actually adapt it, was really important to me. It felt like a promise fulfilled to a chubby 10-year-old me. That book helped me, in a lot ways, and made me realize it was okay to be a little different. I really felt like I owed it to the book to do it right. It was more than a pleasure. It sounds weird to say, but I took it like it was this sacred job I had to do. It was really wonderful.

That’s awesome! Obviously, not every book translates well to film, so what was it that made you see a film in this?

KRIPKE: To me, it was the tone, more than anything else. I still loved the world, and it spoke to a world that people don’t really make as movies anymore, but the thing that I most responded to was that there’s this world where there’s magic bubbling just beneath the surface. It’s this very Midwestern American world that seems very normal, but underneath it is all of this darkness and occult magic, and there was this real danger, even though it was a kid’s book. Real people could get hurt, and there was real evil and real stakes out in the world, but it was leavened with this great humor and an incredible amount of heart. If you didn’t know any better, you would say that I’m describing Supernatural. That’s how directly they are related, and it’s that combination that’s the reason I was confident Supernatural would work. I said, “That combination of heart and scares just beneath the surface, Midwestern Americana, and humor is gonna work because that was what I remember loving, as a kid.”

So, I bought the rights to the book with (producer) Brad Fischer. I knew I could capture the tone, and then we really started looking hard at the plot and realized that we had to adapt it. It’s a different medium, and things that will play in a book just will not play in a movie. You have to find a way to switch it and adjust it without losing the reason you love it. Going in, I thought, “Oh, an adaptation is going to be easy. Finally, I don’t have to come up with my own stuff. I just get to adapt this other story.” And it was so much harder. It was the most stressful game of Jenga that I’ve ever played. It would have destroyed me, if that tower had fallen over because I loved it so much and I felt an obligation to the fans of it to do it right. But you have to move it around and every piece you pull, you’re like, “Oh, dear god, this is the piece that’s gonna knock it over.” It was nerve wracking, frankly, but I think we landed in the right place, with a story that works well as a movie, but still really honors the original story that John Bellairs wrote. We’ll wait to see what the fans say, but I got to talk to John’s wife at the premiere party. He passed away in the late 90’s, but I got to talk to his wife and she said that he would have loved it. That was a legit emotional moment.

That’s so cool! You’ve talked about writing Supernatural Easter eggs into this script. What made you decide to marry those two worlds, and how many made it into the film vs. how many didn’t?

KRIPKE: I got in most of the ones that I was trying to do. Luckily, I never told anybody, so Eli [Roth] and the other producers couldn’t stop and say, “Pull that line! What are you doing?” The reason I did it was that so much of the book made its way into Supernatural that I felt like they’re very symbiotic. They take place in very similar universes. One thing that Bellairs, the author, did that I didn’t realize until I was older, but it blew my mind, was that every piece of occult information in the books is real lore that exists somewhere. And when I ran Supernatural, I had this rule where it all had to be Google worthy, which means it all had to exist in real lore somewhere. That came from the Bellairs. I stole that from him. For instance, I learned that iron was an evil repellent, not from the internet, but from The House with a Clock in its Walls. They used it because it’s a real folkloric thing. It was easy to talk about iron in the movie because that was from Supernatural. And then, once I started making sure that I was mentioning all of the things in the book that helped Supernatural, I just started making references to all of the occult items that were also in Supernatural because they all exist in the same world of real folklore. So, there’s about a dozen or so references made to Supernatural, that anyone who’s a super fan could sit with a pad of paper and find, but what they really are, are references made to real-life folklore that both Supernatural and The House with a Clock in its Walls uses as part of their universe rules.

With the script for the two-hour series finale of Timeless approved by the network and a green light for shooting, when do you start that?

KRIPKE: That shoots in October, I think about mid-October. Arika Mittman, who did the lion’s share of the showrunning in Season 2 and was really quarter-backing a lot of it, will be doing that. I’m there to check in and provide whatever guidance I can, but Arika is very, very good, and so passionate about that show, those characters, and that material. She’s captaining the ship, in a really great way.