Forget AC-12, meet DS-5: Jed Mercurio on his new graphic novel Sleeper

Jed Mercurio has mastered the art, and science, of keeping audiences deeply invested in his intricate, web-like plots. A record-breaking 12 million viewers simultaneously tuned into the final episode of his police corruption drama, Line of Duty, in May, and for those now bereft of his meticulous brand of storytelling, literary relief is at hand. He has teamed up with former colleague Prasanna Puwanarajah, who starred in Mercurio’s 2018 medical drama Critical, to create Sleeper – a conspiracy thriller in the form of a graphic novel series.

Set in the 24th century, and featuring a bionic, deep-space law-enforcement marshal called DS-5, the first instalment has all the ingredients for a ripping sci-fi yarn. There’s mass murder as a space station explodes; a greedy corporation, Texosaturn, that mines clean energy source Titan Green following “carbon wars” on the largest moon of Saturn; and human frailty, as our “biologically enhanced” hero’s ageing tech starts to glitch, and he regains awareness of the person he once was. The action is illustrated by Valencian artist Coke Navarro, a die-hard fan of the shadowy1990s comics Sin City and Hellboy.

Sci-fi was a natural genre for Mercurio and Puwanarajah. The pair bonded on set after, Mercurio says, “I found out he’d been a doctor in the past like me.” Both worked in hospitals before moving into show business (Puwanarajah has written, acted and directed for companies such as the National Theatre and Royal Shakespeare Company and is in the final edits of a Northern Irish road movie he has directed called Ballywalter). “I didn’t know that he was also a writer,” Mercurio says. “He shared some of his work, and I was really impressed with it.”

“We were stuck in a bunker in Egham for nine months’ shooting,” Puwanarajah explains. “And there was lots of time to talk.” He pegs Mercurio as a “classical sci-fi fan”, favouring Captain Scarlet and the works of Isaac Asimov whereas he himself is, “a cheap date – it’s just sort of ThunderCats and trash from the 80s. I was thinking about how sci-fi films and cartoons in the 80s and 90s often seem to be about these bionic naifs. They explored human behaviour through a version of a human that didn’t quite get it.” As a teenager, he related to these characters. “I felt like a person that didn’t quite get it.” This sentiment, he says, collided with “the space western and the police procedural – the Mercurio bit”, and a story started to take shape.

“From my point of view,” Puwanarajah says, “it’s about going: ‘What’s the need for this person to exist in literary form? What’s the hypothesis being tested by their presence in the world?’” The first instalment of Sleeper tantalisingly lays the groundwork for such explorations, as well as the conspiracy plot, establishing DS-5 in his world, and ending, unsurprisingly, on a cliffhanger. A follow-up is in the works.

Mercurio takes a similarly scientific approach to storytelling. Students of his BBC Maestro screenwriting course will know that he borrows from Einstein to view the worlds he creates as space-time, and his characters as matter. Matter, you see, can bend space, affecting said world, along with the trajectories of other characters, but that’s not all. Significant points in a plot are often called “beats” in screenwriting parlance, whereas Mercurio prefers to call them “loci”, which then set matter (characters, remember) on a certain “vector”, and it is these terms that help him keep the story, and its audience, hurtling forwards.

When writing Sleeper, the pair get to flex their scientific muscles within the story itself, as well as in its architecture. “We are interested not just in things as artistic concepts, but also digging into how things might happen in a real world setting,” Mercurio says. “So with the character of DS-5, how that biological augmentation would take place, and the setup on Titan – all those things borrow from our interest in matters scientific.” Unlike working with lay people, as Mercurio has for years on medical dramas, “we can have very meaningful discussions where we understand all the words that we’re using to each other. What’s good about the collaboration with Prasanna is that it’s quite symmetrical.”

Mercurio’s most successful TV shows have rebelled against the industry norm of patronising audiences by embracing the jargon and technical terms used in real hospitals (Bodies) and police settings (Line of Duty, Bodyguard). But sci-fi is a genre in which audiences traditionally expect jargon. “You can go all the way back to 60s Star Trek, where there were neologisms for the technology, there are things that the audience would understand without necessarily knowing the intricacies of, such as the phasers, the communicators, the transporters, and we’re borrowing some of that.” Coming from scientific backgrounds, Mercurio says, “we want to use terminology that feels as if it does relate to how people would talk in this imagined world. It’s something that I personally know works well for the audience. We don’t think that readers are going to feel alienated. It’s something that adds to the reading experience.”

Even the most speculative of their futuristic scientific terms, Mercurio adds, “have a valid meaning”, before clocking that this statement could be seen as an invitation for challenges from eagle-eyed readers. Is that part of the fun? “The fact that people become so invested in the fiction that they start to examine every detail and theorise about what things mean is incredibly rewarding.”

In terms of the aesthetics of Sleeper’s world, the pair agreed that “the future is old … I move more towards a grungier, militaristic feel, like Alien and Aliens, and Blade Runner, rather than the way it was in the original Star Trek series, where it’s very big spaces, and it’s all very flatly lit.” For Mercurio, a credible future world is far from new and shiny. “The technology’s been around a while and so nothing is still in its factory settings, so to speak.”

Sleeper started its life as a TV pitch, and had US commissioners excited. “But we also encountered the issue that it didn’t exist already as a brand,” Mercurio says. The co-writers’ vision involved high production values and big budgets to match, but networks weren’t ready to risk the investment on a concept that wasn’t already recognisable. “We thought: ‘We really believe in this idea, so let’s create it ourselves.’”

Mercurio has published two novels, the first of which, Ascent, is about 20th-century space travel and was subsequently turned into a graphic novel. “But this is quite different,” he says. “And I think that’s exciting, that idea of breaking new ground.”

Having a partner on the project helped keep up the momentum. “If you’ve got two people who believe in something, it creates probably the smallest form of peer group pressure you could imagine,” Mercurio says. “Whereas I think a lot of writers will tell you that if you’re working on your own, and the response to an idea is lukewarm or negative, then you can feel a little bit isolated and unsure how to proceed.”

The change of direction has been a refreshing experiment in distillation. “The process of making a graphic novel is all of the film-making processes happening simultaneously,” Puwanarajah says. “You are considering sequential image storytelling, but you’re also considering in each frame … all the things that you might do in film over a period of pre-production, into production.” His current film project involved about 150 people, whereas, he says, with Sleeper “we’re three people on WhatsApp”.

Navarro says that collaborating with the writers taught him plenty about plot and structure, but it was a learning process for them, too. “When you do a graphic novel you have to think in static images. And these guys think in terms of action and movement.” The writers were surprised by the meticulousness with which Navarro approached the project, drawing diagrams of the space station that would never appear in the book. “Coke guesses nothing,” Puwanarajah says. “How long does it take for them to get from there to there? Is that realistic?” Navarro would need to know, not just anatomically but spiritually, what the characters are like, which, Puwanarajah says, “informs their dynamic range on the page”. In translating the pair’s “screenplay” into images, Puwanarajah believes that Navarro thinks like an actor. “Actors really can’t do things if they can’t feel the reality of it. If they’re inventing something, it always seems to go to shit.”

Once Navarro had drafted each character, he sculpted clay busts of them that he could refer back to as he progressed through the book. When he finally finished drawing the novel with his computer stylus, he texted the team to say: “I think I need to ink these by hand.” The result is that “everything has a hand-drawn-on-paper quality, which is a level of nerdery that I’m really, really into,” Puwanarajah says.

The results are a physical work that the reader can “cradle in their hands, and cherish in a more personalised way than if it’s disseminated through a more collective transmission, like a TV show or a movie,” Mercurio says. With a graphic novel, readers can set their own pace. “It’s a completely different relationship between the passivity of having to go at the pace of the work in film and TV, and the activity of your own reading experience with a graphic novel or a prose novel.” These days, of course, viewers can pause and rewind, but generally, Mercurio says, “they must go at the rate of consumption that the work is transmitted. And so that is a very different, less personal relationship than holding a book in your hands. And having a choice of how long you linger over each page.”

“The thing about graphic novels is they erupt in different ways, the more you scrutinise them,” Puwanarajah says. “There’s all sorts of stuff that Coke has put in that I keep on seeing that’s new. Some person in the back of a cell has got a funny little moustache or there’s a strange building in the landscape.”

There is an intentional nod to the feel of choose-your-own-adventure books from the 80s. “We wanted to include other elements that were different ways of absorbing the story world, that you can go back to in a previous book and see a small piece of context that resonates in the book that you’re in, ” Puwanarajah says. In book one, for instance, there are two separate pages of “unapologetically dense prose that has no kind of context or I guess, foothills. You just suddenly arrive at this thing”. The first is a vividly imagined, obnoxiously wry travel blog about visiting Titan back when it was “bumfuck nowhere”, before Titan Green had been discovered and made it cool, but you could still enjoy the extraordinary spectacle of light dancing off Saturn’s rings. The second is a fascinating article in the Lancet (March 2335 edition) on the science of sleepers, such as DS-5.

All of these layers and details are why, even if the action in the story is happening fast, Mercurio believes graphic novels should be appreciated slowly. “There’s something about the aesthetics of each individual cell, and the way in which they accumulate to give a specific aesthetic to every single page, that is best sipped, rather than gulped.”

• Sleeper by Jed Mercurio, Prasanna Puwanarajah and Coke Navarro is published by Scribner (£16.99) on 5 August. To support the Guardian and the Observer buy a copy at guardianbookshop.com. Delivery charges may apply.