The world of Joe Hill and Gabriel Rodriguez's Locke & Key is about to meet the fantastic dreamscape of Neil Gaiman's landmark comic book title The Sandman in the upcoming crossover miniseries Locke & Key/The Sandman Universe: Hell & Gone. As a collaboration between IDW Publishing and DC Entertainment, the miniseries is a key part of Hill and Rodriguez's latest sweeping Locke & Key story "The Golden Age," as Mary Locke ventures into Hell only to discover it populated by the fantastical characters from the universally acclaimed tale.

In an exclusive interview with CBR, Hill and Rodriguez shared how The Sandman influenced their comic book storytelling sensibilities long before Locke & Key launched, how seamless it was to integrate the two fantasy-horror universes and how generous Gaiman was in allowing them to play in his classic world.

RELATED: How to Read The Sandman and Where to Start

CBR: How did this all come about, this idea to take Locke & Key and Vertigo's flagship title Sandman, and mash them together?

Joe Hill: I mean, it all started out as a daydream, right?

Gabriel Rodriguez: You can be insanely irresponsible when you start pitching ideas that you never think will be on a printed page. Basically, we started discussing a story about a Locke & Key character visiting Hell and, at some point, Joe -- immediately in a huge moment of irresponsibility -- said "What if it's The Sandman's Hell?" and we merged the story of Locke & Key with the universe that got developed in "Seasons of the Mist" arc in The Sandman. And from then on, there was no way to stop, baby. It was too cool not to dive into it headfirst and, also because we wanted to something with this story visiting Hell, we wanted a meaningful idea set in that context so from then on, it started developing very organically.

Hill: At some point around 2012, we had done a story called "Open the Moon" where our Locke & Key heroes visit an afterlife. We started talking that we had seen Heaven so what about Hell? And one of us said "What if the key that Lucifer gives Morpheus in 'Seasons of the Mist,' what if that key was made of whispering iron from Locke & Key?" And that became the leaping-off concept for the larger tale.

Whenever you're doing a crossover story -- be it Frankenstein Meets the Wolf Man or Godzilla vs. Barkley -- you have to make the two universes, in the writing and artwork, mesh. How seamless was it to bring Mary Locke to the Dreaming and Hell? 

Hill: It should've been hard. I think it should've been high-pressure but it wasn't; it felt very organic and natural. It felt like the two universes had always been waiting for each other and I think part of it is that, when Gabe and I started Locke & Key way back in 2007 and first started pitching the concepts around that became the series, our point of reference was Neil Gaiman's Sandman, Alan Moore's run on Swamp Thing, Hellblazer, House of Mystery. Really, our creative context for Locke & Key was the British invasion comics of the '90s that made Vertigo. So in that sense, the story already had some of that flavor.

Rodriguez: Yeah, I remember when I started working in comics in 2002, I remember dreaming for the chance to do my own creator-owned book at some point. And my thought always was I hoped to have the chance to do something like Sandman, like Swamp Thing, like Vertigo, when I get the chance to do my own book. I remember when I got the first script from Joe for the very first issue of Locke & Key, I was sitting in a bus reading the script on my way back home. And I remember reading the first 10 or 11 pages and literally thinking "This is it! This is the thing I've been waiting for to start my very first creator-owned book!"

And from then on, it started developing and growing much bigger and wider than we ever imagined it would. So having the chance to go full circle and return to one of those stories, not only to pay tribute, but because we have a story we want to tell with these characters and these universes colliding together and, as Joe said, how seamlessly they seem to merge, I was very surprised when I got the first draft for Part 1 of the crossover. I started reading it and it felt incredible natural: Nothing felt forced, no character seemed to be pushed into the story. Everything seemed to work with the next piece in a very organic way, like relatives waiting to meet each other. And drawing them was surprisingly easy...the only difficulty it has is the scale.

The scale of the story and the way in which we display these universes in this crossover is insanely exhausting. I think it's the toughest thing I've ever drawn. And even though it feels like two worlds that collided [into] each other as if they were one, I was really surprised; I thought there would be difficulty matching certain corners of this world or characters would feel forced into the plot but it's not; it's incredibly natural.

Hill: Gabe is too humble to blow his own trumpet but that doesn't stop me: I think it's some of his best work ever. Page-after-page, it's absolutely mind-blowing work on a completely new level and that's really saying something because, all the other levels, his stuff has been great. These pages are, visually, absolutely breathtaking.

RELATED: Former DC Executive Editor Mark Doyle Joins IDW

This is the first long-form comic work you've done with Locke & Key in about eight years. How much of coming back is like muscle memory or do you have to warm back up?

Rodriguez: When we started discussing this story, they were going to be short tales that are going to complete the arc of "The Golden Age" which had been told in single issues. I remember when we started setting up the plot for "...In Pale Battalions Go..." and then the "Hell & Gone" story and crossover with Sandman, Joe said "We've got the plot and I think we're going to do a single issue for '...In Pale Battalions Go...' and two 20-page issues to do the crossover so it'll be about 60 pages of work." And I remember immediately thinking there was no way he was going to set this such a small amount of pages so we ended up doing 140 pages of story.

"...In Pale Battalions Go..." ended up being a three-issue series. Even though we stuck to two issues for the Sandman crossover, it grew from 20 pages to 32 to 40 so it's basically a four-issue miniseries set in two single issues. It's going to become the seventh volume of Locke & Key, the largest we've done so far, I think over 200 pages.

Hill: Yeah, eventually it'll all be collected as Locke & Key: The Golden Age and the first chapter of that will be "Small World" and then into "Open the Moon," "...In Pale Battalions Go..." and then a secret story no one knows about that's part of "The Golden Age" that's called "Face the Music" and then there's the Sandman crossover. The Sandman crossover alone is 80 pages, but then there's almost another 80 pages of material that's the rest of the book because "Pale Battalions" is big. When it's all done, it's going to be about the size of one of the legacy editions of Locke & Key.

But to answer your question about if it was hard to come back to write Locke & Key stories: No! I feel more comfortable writing these stories than anything else I do in my life creatively because it's been a part of my life for so long and Gabe and I have a working language together. It's a great collaboration because we share such a sensibility, Gabe gets all my jokes, I get all his visual constructions. We sort of know how the other person wants to tell the story so it just flows. When I was a kid and wanted to be a writer, I always imagined having my own series like Sherlock Holmes or Philip Marlowe or James Bond. I never imagined my series character would be a house, but I'll take it. [Laughs]

RELATED: TMNT: The Last Ronin #2 Is IDW's Highest-Printed Single Issue Ever

Rodriguez: It's great to see how an experience pays off. One of the things I've been discussing with Joe and the editors on the book is, for the first time, I feel like I have all the tools that I need to tell the story of these worlds in a proper way. When we returned to the world of Keyhouse in "Pale Battalions" -- which was an ambitious story in terms of the kind of drama we wanted to tell and a war story that was going to be meaningful -- we succeeded at that because we somehow did it at the right time. The entire thing feels like coming home, the previous run of Locke & Key prepared us to do this in a right way.

So despite it being incredibly exhausting because of the ambition and the huge scale, just finishing the pages has been a thing that's drained me but in a way that I have everything I need in the arsenal to pull off the story in a proper way. We only ask the reader to have patience and wait for the pages to be done as soon as possible but we also want to tell the story in the right way. We don't want to rush anything that could damage the quality of the stuff we're pulling off because we know this is a once-in-a-lifetime chance to do something like this, and you have to do your very best and treat the story with the respect it deserves.

Hill: Writing is a mostly lonely experience, and working on Locke & Key, you have all these collaborators who are completely into it and we've been doing these stories for over a decade. We really have down our system of working together, it's very fluid and natural and we know each other's strengths and weaknesses and sensibilities. For me, it's the closest I'll ever be to knowing what's like to being in the fucking [Rolling] Stones because we all feed off each other's energy. It's not just me and Gabe: Jay Fotos has colored every single issue of Locke & Key; he's just masterful with his use of light. There's something so weightless about the pages because of the way he lights them, the sense that he's not just coloring but creating a sense of where the light is coming from and the particular mood and illumination.

Rodriguez: He understands the way in which we make this dramatic storytelling work. As Joe said, to have the same collaborators for the entire thing, since we started the first issue of Locke & Key, has been great. To have Jay on board and Chris Ryall on board, it makes everything easier because it's like a band that comes together again and starts jamming and flow easily. We know each other's strengths and how to push one another to get the very best. For me, it's a pleasure to finish a page in black and white and get it returned in full-color by Jay Fotos and realizing that, in your own artwork, you discover new things because of the way Jay colors and completes it. It's fantastic and, when you the combined thing with text, you feel like the story is driving you to get that exact thing out of it.

Hill: By the same token, Chris Ryall -- who has been the editor on every issue -- he's good at knowing in advance what a story will need, well before Gabe and I know how many pages we're going to need; Chris already has it all figured out. When I say we're going to need a third issue of "Pale Battalions" Chris is just like "I know...it's already on the schedule."

If we're talking Sandman, we'd be remiss if we didn't mention Neil Gaiman and if the Locke & Key team is the Stones, he's like David Bowie. How was it working in the worlds he created and running things by him?

Rodriguez: One of the things we've mentioned time after time is Neil's work is what got us back into comics when we younger and how could you not fall in love with a universe like with Sandman's? He created a fantastic story but the way he reinvented comic storytelling and fantasy stories for a new audience. Lots of people who never read a comic before got their entry point through Sandman because it was both incredibly challenging for readers but also welcoming. And I think it's part of the magic Neil brought to the pages, not only creating these insane concepts but also to make the reader feel welcome in that world. It educated an entire generation of creators, Neil and all the artists that worked with him that created this fantastic world.

For me, the biggest responsibility here is to say thank you in the proper way to Neil Gaiman and all those artists and editors all led by Karen Berger who brought Vertigo Comics to life in the late '80s and early '90s and who discovered great writers and amazing artists but also a way of comic storytelling that is the reason Locke & Key exists. Another thing is how joyful and generous Neil has been to let us play with his toys and tell our story and, thankfully, he recognized we were doing this with as much respect as possible ad also being irresponsible because we're doing such big things with these characters in this story that we were, at points, a little scared that we were not allowed to get away with it. But Neil has given us his blessing.

Hill: Neil is a tremendously generous man with luminous imagination. We learned how to tell Locke & Key from reading Neil's comics; Neil was sort of a primary teacher for Gabe and I what was possible in the format and the broad range of stories possible to tell. We always talk about Locke & Key in the context of Sandman. Neil said a thing while Sandman was still going on that I read in a print comic magazine: He realized he could use the concept of dreams to tell any kind of story he wanted. He could tell a horror story, he could tell light fantasy, he could do a comedy or historical; the idea of dreams became a sort of instrument he could use to leap off to any genre or form.

And early on in Locke & Key, it came to me that keys could work the same way: You could use the keys to tell a coming-of-age story, a horror story, weird fantasy, all those possibilities were open. I thought the keys are for us what dreams are for Sandman. Neil's thinking about comics was instrumental to our own, and it was very kind of him to let us do this and let us plunge into his universe.

Written by Joe Hill and illustrated by Gabriel Rodríguez with colors by Jay Fotos, Locke & Key/The Sandman Universe: Hell & Gone #1 goes on sale April 14 from IDW Publishing and DC Comics. Locke & Key Season 2 is set to debut later this year on Netflix.

KEEP READING: Neil Gaiman Explains the Difference Between Sandman and Lucifer’s... Lucifer