Jonathan Leahy was 11 when he saw a goofy movie about two bodacious teens who travel through time to complete a history project. “I was raised by old-fashioned parents in a conservative part of the Northeast,” Leahy says, recalling when Bill & Ted’s Excellent Adventure first came out. “I almost certainly saw it on VHS at a friend’s house without my parents knowing.” He was captivated by the film’s positive vibe, and its titular bozos, played by Alex Winter and Keanu Reeves.

Thirty years later, Leahy — now a music supervisor with credits like Mr. Robot and numerous seasons of Girls — was tapped to wrangle the music for the long-awaited third entry in the franchise, Bill & Ted Face The Music, which had been trapped in totally bogus development hell for nearly a decade. Music has always been important to the franchise — from the duo’s own endearingly bad band, Wyld Stallyns, to their recurring obsessions with Van Halen and Iron Maiden, to the Battle Of The Bands from Bill & Ted’s Bogus Journey.

Now, it’s crucial. The new film’s plot — a barely coherent vehicle for Winter and Reeves to revive their still-potent onscreen chemistry — revolves around Bill and Ted, now flailing dads in their 40s, being tasked with creating a song that can restore harmony and unity to the world. In the process, they visit their future selves and endure another dalliance with the Grim Reaper (a pretty solid bassist). Their teen daughters, meanwhile, travel through time like Bill and Ted in the original film, recruiting musical geniuses like Jimi Hendrix and Mozart to beef up their dads’ mediocre band.

Leahy — along with the film’s score composer, veteran musician Mark Isham — was tasked with creating and curating the music that holds the ludicrous plot together. It’s a lofty assignment: How do you create an original song that might conceivably save the world? We spoke with Leahy and Isham about the stories behind the film’s notable musical moments. (WARNING: This piece contains some minor spoilers about Bill & Ted Face The Music.)

THE LEGENDARY AIR-GUITAR SHREDDING
One of the most beloved conceits of Bill & Ted’s Excellent Adventure is that, although Bill and Ted are not especially good at guitar, they do perform bodacious air guitar licks whenever they get excited. Like, for instance, when they’re in a castle in medieval England and misinterpret the phrase “iron maiden”:

In 1991’s Bill & Ted’s Bogus Journey, the air guitar licks were notably performed by Steve Vai. For Face The Music, director Dean Parisot wanted to get someone new. “He said, ‘What does shredding sound like in the year 2020?'” Leahy recalls. “And my answer to that was, ‘It sounds like Tosin Abasi.'” So the music supervisor commissioned guitar virtuoso Abasi, best known for his prog-metal band Animals As Leaders, to perform the air-shredding snippets. (Maybe next time, St. Vincent.)

THE DREADFUL WEDDING SONG
When we first meet the middle-aged Wyld Stallyns, they’re performing a song called “That Which Binds Us Through Time: The Chemical, Physical And Biological Nature Of Love; An Exploration Of The Meaning Of Meaning, Part 1″ at the wedding of Ted’s younger brother, Deacon, to his hot ex-stepmom, Missy. The song is atrocious, a cacophonous melding of throat-singing, blues riffs, and highly unwelcome bagpipes, all of which provoke the consternation of Ted’s dad (the instantly recognizable Hal Landon, Jr.).

This posed a challenge: How do you create a piece of music that’s bad, but in a funny way?

“We had a thousand different conversations about how bad should it be,” says Leahy. “What we decided was, number one, it had to be difficult to dance to. Because we have Deacon and Missy attempting to dance to something that is not easily danceable. Next we wanted to come up with a complement of instruments that would be fun to see Alex and Keanu perform on. I’m sure somewhere there’s a 30-minute cut of the scene where they play all the instruments onstage.”

Leahy estimates there were 20 different mock-ups of the song prior to shooting. But when it came time to film, Winter and Reeves didn’t want to shoot to a backing track. “They were like, ‘No. We got this. We’re gonna do our thing,'” Leahy recalls. He’s glad they did: “Them attempting to mime along with a prerecorded track would have been so much less funny.”

But now there was a new challenge: reconstructing a piece of music that matched what was being performed onscreen. Mark Isham, the film’s composer, took a pass at it. “I tried to make each gesture reasonable on its own,” Isham says. “And then the juxtaposition of these things together just sounds ludicrous.” (Isham’s version wasn’t ultimately used.)

“It’s not an… incompetent piece of music,” Leahy says of the ultimate result. “The goal was to make it seem as if they were trying so hard, and searching so wide, to find a combination of sounds that might save the universe that they ended up in this ridiculous place, where they would play the theremin and the steel drum and bagpipes and trumpet.”

THE SONG THAT SAVES THE UNIVERSE

At the start of the film, the two heroes are given a ridiculous assignment: They must write a song that unites all earthly reality, before the clock runs out.

For Leahy, this wasn’t fiction. “At some point, I realized that the challenge that Bill and Ted face, and the anxiety they face in the movie — that was actually my problem,” he laughs. “And the whole music department’s problem in real life. It was all hands on deck. We had tons and tons of outside writers and producers throwing ideas at it.”

Early on, the team decided that the track should have a wordless hook that the whole world could sing along with. “We had some very short, 30-second repetitive hook ideas,” Leahy says. “Something akin to a football stadium chant. Something that transcended language, basically.”

The plan was to have a mocked-up recording approved prior to filming, then use that playback on set for the cast to mime along with during the shoot. That didn’t happen. “So we went into that week of shooting with no song,” Leahy says. “And it started to feel very much like the plot of the movie! It was like, ‘We don’t have the song!'”

After deciding on a tempo, the director shot the scene to a click track instead. While completing the track, the music team had to work backwards from what instruments were shown onscreen. The final song centers around a big, gushing “Ohhh-ohhh!” chorus and major-key guitar heroics swirling together in an inoffensive haze. “We were just going for a mood,” Leahy says. “We wanted to sonically make it sound like it had the power to heal the universe.”

JAMMING WITH ROYAL UGLY DUDES
If you’ve ever wanted to see Jimi Hendrix, Mozart, Louis Armstrong, and Ling Lun play in a band together, here’s your movie.

Remember how Excellent Adventure had Beethoven (“BEETH-oven”) jamming at the mall keyboard display?

The new one borrows that conceit and makes it a main plot, with Bill and Ted’s daughter-doppelgangers bouncing through time and plucking musical geniuses from their natural habitats. In one scene, Hendrix time-travels to 18th-century Vienna and begins shredding in the middle of a Mozart performance. “What you hear during that scene is entirely Ray Suen,” says Leahy, referring to the outrageously talented multi-instrumentalist who’s been a hired gun for the Killers, Lorde, and Flaming Lips. “He can play guitar and piano and keyboards. So when I see the script page that has Mozart playing with a violinist in the background dueling with Jimi Hendrix, my first call is to Ray Suen.”

The Mozart piece is Piano Concerto No. 16. “We were looking for something instantly recognizable,” Leahy says. Disappointingly (or thankfully, depending on your view), there are no actual Hendrix songs in the film. We do hear him play “Amazing Grace” (which is in public domain) and original Hendrix-like material created for the film. In addition to Suen, guitarists Joshua Ray Gooch and Cory Churko recorded some of the Hendrix guitar bits.

As for Louis Armstrong: “I felt a tremendous pressure to not mess that up,” Leahy says. “I made one phone call only, and that was to [jazz trumpeter] Christian Scott.” Scott performed most of Armstrong’s trumpet parts in the film, though Mark Isham provided some of the trumpet parts during the world-saving song.

THE FILM SCORE
For the score, Leahy commissioned Mark Isham, a veteran composer who’s scored an illustrious range of films, from Short Cuts to October Sky, not to mention guesting on albums by XTC and Joni Mitchell. (Notably, Isham also scored Werner Herzog’s batshit Bad Lieutenant remake. He says Herzog gave him very cryptic instructions for that film: “If you understand the bliss of evil, you will be fine.”)

For Bill & Ted, Isham wanted to move beyond the dated glam-metal aesthetic of the original films. “I decided to take the futuristic sound of traveling in space and make it distinctly not guitar,” he says. He busted out his old ’80s synths, including an old Moog and a Prophet-5.

Isham arranged the score remotely during the pandemic. He feared he would need to ask orchestral players to record their parts at home, then mix the tracks together. Ultimately, he managed to use an orchestra in Budapest while the US was on lockdown, and the score was recorded there.

THE DEPRESSING OPEN MIC SONG
In one of the film’s time travel sequences, Bill and Ted encounter their future selves performing a fist-pumping anthem called “Those Who Rock” at a sparsely attended open mic. The track was co-written by a musician named Wendy Wang. But the music really was performed by Winter and Reeves.

“I arranged for Wendy to go to New Orleans for a week, to guide them through playing that song, as well as helping them with other instruments,” says Leahy. “I believe that’ll be the only time you hear Alex and Keanu performing completely authentically as Wyld Stallyns.”

Considering Reeves plays bass in real life, that song probably wasn’t hard to learn. But in his dedication to the role, Reeves assigned himself a much trickier challenge: learning bagpipes. “One of my fondest memories was getting an email saying Keanu wanted to learn how to play bagpipes [for the wedding scene], and could I arrange for a New Orleans-based bagpipes teacher to work with him in the next 24 hours,” Leahy says. “It’s a fond memory now, but it was stressful at the time.”

Leahy found one. For a while, he spent much of his day coordinating music teachers. (He also arranged trumpet lessons.) But the bagpipes instructor was most impressed by the Matrix star. “Keanu was absolutely determined to play the bagpipes correctly,” says Leahy. “I talked to the teacher after he finished and she was like, he was the best student she ever had. She said, ‘He learned it super fast and is completely dedicated and serious about the process.'”

THE SOUNDTRACK
The original Bill & Ted soundtracks are time capsules from the late hair metal era, populated by long-forgotten tracks by bands like Extreme, Winger, and Slaughter. (Also, Primus. Did you know Primus has a cameo in Bogus Journey??) When it came to choosing non-Stallyns bands to contribute to the Face The Music soundtrack, Leahy didn’t want to lean on bands from that era. “That would be like putting Elvis into Excellent Adventure,” he says. “That’s just absurd.”

He did, however, want to honor the franchise’s connection to metal, so he nabbed more relevant metal bands, like Mastodon and Lamb Of God, to contribute songs to the film.

There’s also a scattering of onscreen cameos: Dave Grohl and Win Butler both make brief appearances, and Kid Cudi has an actual, sizable role as himself. (If it’s starting to seem like this script was written in 2010 — well, it was.) But the band whose involvement has generated the most headlines is Weezer, whose song “Beginning Of The End” plays over the end credits. (Say what you will about late Weezer, but the band’s bizarre longevity does seem primed to unite the Gen-X Bill & Ted crowd with younger viewers.)

When Leahy reached out to Weezer’s management, he learned that Rivers Cuomo was a fan of Bill & Ted. Conveniently, the band had a trove of unreleased material for Leahy to consider. When Leahy heard “Beginning Of The End” (recorded for the forthcoming Van Weezer), he was struck by one lyric: “Watch us brush off the dust/ In heavy metal we trust.”

“When I heard that line, I was like, ‘OK, I think this might be the song,'” Leahy says. “Then 30 seconds later, when it goes into the guitar solo and it’s just epic, two-handed tapping, I was like, ‘OK, this is definitely the song.'”

Bill & Ted Face The Music is out 8/28 in theaters and on demand.