With “Game of Thrones,” HBO wove dragons, swordfights, and blood magic into a demographic-crossing television hit. Now it hopes to do the same with robot cowboys and mad scientists.

Based on Michael Crichton’s 1973 film about a theme park filled with thinking, human-like machines gone haywire, “Westworld” premieres Oct. 2 on the premium cabler. Humongous in scope, the show is an ambitious gambit at a critical time for HBO, which could use a big drama to carry its flag past the looming end of “Game of Thrones.” To give “Westworld” a chance at becoming that show, HBO’s marketing team is using technology that mirrors the world of the series to rally hardcore fans.

“We knew that there would be two distinct strategies,” says Sabrina Caluori, senior vice president of digital media and marketing for HBO. The first of those is the theatrical-style campaign of on-air, online, and outdoor advertising that is a must for a big-series launch.

“The second,” Caluori says, “given the pedigree of the producers, as well as the content and the rich story world, is a primarily interactive campaign that was targeted at sci-fi fans, tech enthusiasts, and the fans of our producers.”

Those producers are the husband/wife team of Jonathan Nolan and Lisa Joy — he of “The Dark Knight” and other collaborations with his brother, Christopher Nolan; she of “Burn Notice.” They serve as principal writers and showrunners on “Westworld,” and executive produce alongside J.J. Abrams. They also worked closely with HBO on the series’ marketing, from the poster tagline — “Every hero has a code” — to a virtual-reality experience and a microsite that will serve as a hub for fans looking to dive deeper.

“With ‘Westworld,’ there were really good opportunities to bring the park out into the real world and break that fourth wall,” Nolan says. “So we talked about all of the ways that we could actualize the park in the real world.”

One of those was VR. Last year, HBO invited Nolan and Joy to demo the HTC Vive — the first time either had tried the technology. Joy described feeling “reality shock” after removing the headset. “It’s such an interesting, immersive way to tell a story, and it dovetails so nicely with what we’re doing with ‘Westworld,’” she says.

Fast-forward to September, and the premiere of a VR “Westworld” experience created by series staffers at TechCrunch Disrupt.

The price of a headset such as the Vive starts at $799. That makes VR among the least accessible platforms on which to market a television show. HBO understood and embraced that; after all, a trip to Westworld does not come cheap.

“We built something that was highly immersive and interactive,” Caluori says. “The fact that we didn’t get scale out of it from a consumer perspective matched with the overall strategy of both reaching that tech influencer but also continuing to drive home the exclusivity of Westworld as a park destination.”

Matching that strategy is the microsite, DiscoverWestworld.com, which resembles the website for any luxury resort. But it has darker substrata for the frequent user to dig into. As the series progresses, it will be a portal through which fans can unlock additional content, all of which will have input from Nolan, Joy, and their team.

Such promotional tools are not new; Caluori says it was “a no-brainer” to build a realistic theme-park site. The site for ABC’s “Lost” was a leap forward in the science of sucking time from super-fans. But tech advances have ripped the ceiling off how innovative such sites can be. If “Westworld” delivers creatively, the site could be one way to not just lure a fan base, but to keep it fed.

“Your most engaged and passionate fans, particularly when we’re dealing with a genre show, can be your greatest advocate,” Caluori says. “So that’s for us the reason to build out this very rich experience. If we can create something cool, they’ll help to drive the overall word of mouth and success of the show.”