Making a documentary can be hard, but making a documentary without your main subjects might seem nearly impossible. Sara Dosa rose to that challenge while directing “Fire of Love,” which tells the story of famed French volcanologists Katia and Maurice Herber, who spent their lives documenting every volcanic eruption they could on video. Some decades later, Dosa was able to use that footage (more than 200 hours of it, without any sound) to craft a narrative that is, as she puts it, “a love triangle story, a story about these two humans who also have a love relationship with a volcano.”

“We probably watched about 250 hours of footage. About 200 of that was original footage that Katia and Maurice Krafft shot, and then about 50 hours was recordings, documentaries, television, broadcasts of Katie and Maurice themselves,” Dosa told senior artisans editor Jazz Tangcay for Variety‘s Doc Dreams presented by National Geographic. “Because there wasn’t sound, we had to do a ton of research to try to really understand what we were looking at. Luckily, Katia and Maurice provided that information for us. They authored nearly 20 books. There’s many biographies about them. There’s documentaries that had been made about them when they were alive.”

While Dosa’s team re-created much of the natural sound, from car engines to noisy explosions, they were also led by a more abstract approach, in which they were “guided by a sense of intuition,” as Dosa put it.

“We tried to rely, actually, on some of the tropes and hallmark style of the French New Wave as a guide,” Dosa said. “The French New Wave very much formed the cultural backdrop when Katia and Maurice were coming of age. One of the hallmarks of that aesthetic movement was associative editing. For us, when we had all of these pieces from all around the world, beautiful imagery, but a lot of times, we would be met with juxtapositions that didn’t quite make sense to us. We would be guided by a sense of intuition about how to put those together.”

Watch the full video above.