Panos Cosmatos explains why he found a natural kinship with the composer for his heavy metal cult hit.

In “Mandy,” Nicolas Cage goes on a wild-eyed quest for revenge, but the movie’s plot comes secondary to the experience of watching it. Director Panos Cosmatos’ follow-up to his similarly atmospheric “Beyond the Black Rainbow” is a heavy metal tone poem, replete with leather jackets, shadowy landscapes, and unfiltered bursts of rage. Much of its expressionistic power comes from an undercurrent of music that envelops nearly every moment, evoking dread and wonder in equal doses.

The “Mandy” score is one of the best of the year, a fierce emotional arrangement of mournful synth and somber guitars, interspersed with jarring eruptions of percussion — all of which demonstrate the complex vision of Icelandic composer Jóhann Jóhannsson, who died in February at the age of 48, shortly after “Mandy” premiered at Sundance.

Now, as “Mandy” has catapulted beyond its initial day-and-date release to become a genuine cult phenomenon, its creators have been campaigning to remind people of Jóhannsson’s legacy (and dreaming of awards potential in the process). Several vinyl editions of the soundtrack have been released, and they feature the full scope of Jóhannsson’s work on “Mandy,” including the spectacular “Children of the New Dawn,” which did not make it into the final cut of the movie.

“I was really happy with his work, but I also felt in a way that we had only just scratched the surface of what we could do together,” Cosmatos said in a phone interview. “I was actually looking forward to working with him again, and going even further.”

Jóhannsson was an established Hollywood composer by the time “Mandy” came along. After collaborating exclusively on Icelandic projects throughout the aughts, he eventually developed a prestigious repertoire that included the bulk of Denis Villeneuve’s English-language work — “Prisoners,” “Sicario,” and “Blade Runner 2049” — as well as “mother!” and “The Theory of Everything,” which scored him an Oscar nomination.

However, Jóhannsson’s “Mandy” connection emerged out of his first American project, the 2013 thriller “McCanick.” That movie was directed by Josh Waller, co-founder of the genre production house Spectrevision with producer Daniel Noah and Elijah Wood. Jóhannsson had also been a client of the company’s short-lived Spectrevision Music Management, and when he heard that the company was producing Cosmatos’ sophomore effort, the composer reached out. The dark, lyrical project was a world away from the bigger productions Jóhannsson had tackled in recent years, but Cosmatos’ affinity for heavy metal resonated with Jóhannsson’s own passions.

“He was always on our minds for the film, but he reached out to us,” said Wood. “He said, ‘Man, I’m a big fan of Panos. Do you think there’s, like, room at the table for me on this movie?’” A fan of “Beyond the Black Rainbow,” Jóhannsson felt the need to plead his case. “His perspective was, ‘Holy shit, you guys are making something with Panos that is in this nightmarish, psychedelic metal world that I was born and bred on,’” Wood added.

Cosmatos had been admiring Jóhannsson’s work from afar, and said that a single cue in “Sicario” had stuck with him. “They’re descending into this valley at desk, and there’s this unbroken shot of blending into the darkness, and I just thought it had one of the truly greatest music cues in cinema history,” Cosmatos said. “I’m not exaggerating.”

Nevertheless, Cosmatos had grown used to working on a small scale and the idea of enlisting a revered composer of Jóhannsson’s stature had not occurred to him. The Spectrevision team arranged a phone call between the pair that wound up lasting several hours. “I realized we had some similar touchstones,” Cosmatos said, noting that they bonded on a shared affinity for Van Halen in particular. “I said that I basically wanted it to feel a little bit like a disintegrated rock opera, and he responded to that. We developed a kind of shorthand almost immediately.”

Jóhannsson was so eager to take on the project that he went beyond the typical workflow procedures and began composing before seeing any footage of the movie. “He was composing ideas and sketches just based on the script itself,” Wood said, “so even during the pre-production process, before they started rolling cameras, there were little bits of music, sketches, and ideas that he was expressing. It was extraordinary.”

Jóhannsson enlisted the Seattle-based experimental metal band Sunn O))) to provide the moody guitar work, not even realizing that Cosmatos had already appreciated the group’s work on the soundtrack to Jim Jarmusch’s “The Limits of Control.” Cosmatos had listened to that song while preparing to work on “Beyond the Black Rainbow,” so it was clear that Jóhannsson understood the wavelength of his newfound collaborator. “I felt like somebody who had experience working on more traditional movie scores might actually benefit the film, because had a base to build from, and mutate from,” Cosmatos said.

Jóhannsson assembled the soundtrack in piecemeal, sending sample bits to Cosmatos via email and working from a rough cut that had no temp score, per the composer’s preference. They only met in person once, after the movie had been completed. Cosmatos described their phone calls as idiosyncratic planning sessions that reflect the undulating tones of the movie. Describing the opening sequence, which establishes the Cage character’s utopian existence with his wife (Andrea Riseborough) before a deranged cult shows up and destroys everything, Cosmatos swung for specifics. “I said, ‘I want it to feel like you’re 11 years old, and you’re in the backseat of your big brother’s Trans Am, and he’s smoking weed, and you can smell the vanilla air freshener, and the leather,” the director said. “It’s kind of scary, but it’s also exhilarating at the same time.” Cosmatos recalled that Jóhannsson paused before replying: “I know exactly what you mean.”

In the aftermath of Jóhannsson’s death, Cosmatos hasn’t revisited the soundtrack. “I’m almost afraid to listen to it in isolation, because I still have emotional strands attached to it,” he said.

The filmmaker, whose father George Pan Cosmatos was a filmmaker with credits ranging from “Rambo: First Blood Part II” to “Tombstone,” said he forged a familial bond with Jóhannsson over the course of their collaboration. “I did feel a closeness to him in a weird way,” Cosmatos said. “He reminded me a bit of my dad in a sense. He had a gruffness about him, but once you spend some time with him, you realize he’s a very sensitive, thoughtful person. Our friendship was just beginning.”

“Mandy” is now available on DVD and Blu-ray. The soundtrack is available now from Lakeshore Records.

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