When your favorite YA stars trade sun-drenched beach houses for dark, turbulent ocean waters, audiences know they are in for a ride. In the creature feature The Devil’s Mouth, a familiar ensemble of YA fan-favorites comes together to swap coming-of-age romance for pure, shark survival horror. Set against the breathtaking yet terrifying backdrop of Thailand‘s open oceans and cavernous underwater systems, the film bridges the gap between high school heartthrobs and high-stakes genre.

The Devil’s Mouth stars Lana Condor, Gavin Casalegno, Kathryn Newton, Nico Hiraga and Tommi Rose. The film follows a group of friends who go on an adventure in Thailand but are stalked by sharks in a cave.

For the cast and crew of The Devil’s Mouth, filming a shark thriller meant wading straight into pure, unadulterated madness where they spent up to 13 grueling hours a day submerged in real open ocean swells and subterranean cave systems across Thailand.

As Condor reveals, the physical toll was entirely real. “We were in or under the water for 12 to 13 hours a day,” Condor explains in a virtual interview. “Like we were in that water, in those systems, cave systems, oceans, all of these things for real. I think that maybe people might think that it’s not real water, maybe or whatever. No, like we were in massive cave systems.”

To make the survival instinct on screen palpable, director Jeff Wadlow used life-sized bull shark diorama for close proximity work while the crew built a custom mechanical rig featuring a genuine shark fin mounted atop a high-torque underwater motor that chased the actors through the waves.

Condor recalls how the raw setup triggered instant, genuine biological terror. “They put a fin. They motorized a fin and so when all of those shots of us swimming away, like looking back and screaming, that was because we were being chased by a real fin, and that feels very real,” Condor recalls. “Like if you see a fin in the water, even if you know it’s fake, the body doesn’t know. Like your body just reacts like crazy, so that stuff is very fascinating.”

Directing on open water forced the crew to reinvent standard equipment on the fly, as traditional rigs were far too heavy underwater. Wadlow partnered with local Thai technicians to mount waterproof cameras onto motorized “Aqua Bobs,” sea kickboards that allowed operators to zip through the waves right alongside the cast. Basic set routines like hitting marks also proved impossible on the seabed, forcing the team to improvise floating markers. As Wadlow notes, “What they don’t know about making a shark movie is that it is way harder than you think. Being in the water is a challenge, and our shark movie takes place entirely in the water… Normal things you do on a movie set, like hitting a mark, becomes quite difficult because you can’t put a mark on the ground. We actually had this thing where we had floating bottles on weights to kind of try to mark generally where the actors would be. So, water makes everything harder.”

For years, Condor, who starred in Jenny Han‘s To All the Boys I Loved Before franchise, has been synonymous with heart, warmth and relatable charm, but The Devil’s Mouth marks a complete transformation in her screen presence as she steps into the shoes of Max, a ruthless, hyper-dominant friend.

Condor was actively searching for a complete tonal shift and embraced the opportunity to play an unapologetic, manipulative character. “Oh my god, I loved it,” Condor reveals. “It was really freeing to play someone who is aggressive and like a bitch and incredibly dominant and believes that it’s her way or the highway. I like that and to release yourself of having to be charming is really incredible. Max is more manipulative than charming. It was so great to be able to do something like that and experience that.”

Beyond stepping into her villain era, Condor was particularly drawn to the inverted mechanics of Max’s emotional trajectory compared to standard genre heroines. Rather than starting quiet and timid before discovering her inner strength under threat, Max is introduced at her absolute peak authority before the grueling environment systematically breaks her down. “I think what I love the most about her arc is that I’ve played a lot of characters that kind of start like more inside of themselves and then they blossom,” Condor says. “The difference in this one is that you meet her fully blossomed and then she slowly is defeated and that was a really fun change for me to be able to do. I really hope I get more opportunities to do that.”

Adding a meta-layer of fun for young Hollywood fans, the film reunites Condor with Casalegno, who starred in The Summer I Turned Pretty franchise, making the thriller a surprise collision between two prominent veterans of Jenny Han’s screen adaptations.

Casalegno, who was equally eager to step away from romance-drama to try a completely different genre flavor after years on The Summer I Turned Pretty, relished testing new waters. “It was one of the things I looked forward to the most, kind of exploring something new and exploring a different genre. I think that was such a treat,” Casalegno shares. “I think doing the same thing for five years, which is such a blessing, and I’m so grateful for it. But trying a new flavor of stuff was awesome, and getting to work with this cast was so phenomenal. There was never a dull moment. We just had so much fun.”

That creative excitement only grew when Casalegno and Condor realized their shared connection to Han’s universe during their very first table read. “Lana’s awesome. We looked at each other when we first met at the table. We’re like, ‘We got a lot to talk about’ and just like our experiences, and just how fun it was on set,” Casalegno recalls. “And we both Facetimed Jenny, and we’re catching up. It was funny seeing her like so excited that her worlds are colliding. Lana is so amazing, so professional, so lovely to work with. She’s a pro at what she does.”

Beyond the shark threat, the emotional core of The Devil’s Mouth lies in testing female friendships that have shared history under ultimate pressure. Rather than a united squad facing a threat, social etiquette instantly shatters when survival is at stake. As Condor points out, the real threat might be floating right next to you: “I think that’s the heart of the film. We wanted it to feel like you are terrified because of the shark, but you’re also terrified because you see a friendship that has a lot of history… Like in the beginning, you want to feel like oh, this relationship is really toxic. Like something’s wrong. Maybe it’s not a shark movie. Maybe it’s a twist, and maybe she’s gonna kill them all. And we wanted it to be like how, like the relationship is the shark, right?”

Newton echoes that sentiment, adding that those raw interpersonal stakes give the thriller its emotional weight: “It was definitely rooted in friendship about a group of friends going on this last adventure of a lifetime together… I think a lot of young people can relate to the friendship aspect, you know, having to leave your friend, and also your best friend really knows you. You can’t hide from them… Sometimes you need to be left behind, and sometimes you need to learn how to stand up for yourself and be okay with losing everything.”

Co-star Rose notes that the script deliberately embraces the realistic gray area of female friendships under survival pressure. Rather than painting characters as purely supportive or malicious, the film highlights how real people navigate life-or-death hurdles: “A lot of the time, there can be a lot of competition between women. There can also be wonderful female friendships that are perfect all the time, but I think that there’s not a lot of exploring the gray area like sometimes you can have an amazing friendship and sometimes something gets in the way or something comes up as a new hurdle to get past… I think that the girls in this script are really interesting in the way that like they’re not always wrong, but they’re also not always right.”

Hiraga brings a softer, grounding element to the group’s frantic survival struggle, focusing on his character’s deep emotional anchor amidst the ocean chaos: “What I loved about playing him was his sympathetic side, his sensitivity to the situation, and his love for his girl.”

On the final day of production, the entire cast walked down to the beach in Chiang Mai as the sun began to set to mark the end of their journey. Newton recalls the emotional wrap moment as a beautiful capstone to an unforgettable shoot. “There’s really nothing better than being trapped on a movie. I’m filming right now, and everyone’s in the same hotel. And you run into each other going to get dinner, going to the gym,” Newton recalls softly. “And one of my favorite moments was in Chiang Mai, I think, where we all wrapped, and then the cast we went swimming in the ocean at the beach, and like the sun was setting, and like we all made wishes, and you know that was really cool. I’ll never do anything like that again with anybody. It’s a really intimate relationship you build by making a movie together.”

The Devil’s Mouth is now streaming on Prime Video.