When Lara Jean Gallagher cast Otmara Marerro as the lead of her debut feature “Clementine,” she knew she had an actress who could pull off all the emotional complexity of Karen, a spurned lover who breaks into the lake house of her ex-girlfriend D to retrieve their shared pet Ramsey and ends up staying for a while in the idyllic locale to get some peace of mind. There was only one problem.

“It turns out when we did show up on set, we found out that Otmara was actually allergic to dogs, but she didn’t tell us,” recalls Gallagher. “She said, ‘My mom couldn’t believe that I didn’t tell you that I was allergic to dogs!’ And I was like, ‘I can’t believe you didn’t tell us you were allergic to dogs!’” But then I just warmed to the fact that she really wanted the part and I [thought], ‘Yeah, that’s totally something Karen would do, so I’m on board with it.’”</

It doesn’t take long to see why Marrero was willing to risk getting some hives to star in “Clementine,” a cool, elusive drama that at once feels like a throwback to French thrillers of the 1960s such as Rene Clement’s “Purple Noon” and Jacques Deray’s “Le Piscine,” but feels distinctly modern in its aesthetic and narrative sensibilities. Set in the Pacific Northwest where there’s always a slight chill in the air, even during what seems like summer, the film joins Karen indulging in the most juvenile response to a devastating breakup, yet finds herself unexpectedly in a position of authority upon meeting the 19-year-old Lana (Sydney Sweeney), who stops by to sunbathe and swim in the lake. As Karen pushes 30 and grapples with being considered too immature for the older D to commit to, she’s thrust into seeing things from D’s perspective as Lana takes an interest in her that could go beyond friendship, with Karen gingerly navigating the maternal feelings she starts to have for Lana with the physical attraction that the two begin to have for each other.

Following the maxim that a gun uncovered in the first act must go off by the third, “Clementine” has your more traditional intrigue, but the real danger lies in how meticulously Gallagher and stars Marerro and Sweeney evoke a relationship where every moment has the potential to combust, with Karen carefully attempting to not leave Lana with the scars that she has herself from the experiences she’s had while trying to move on and following her passion wherever it may lead. With cinematographer Andres Karu filming inside the house with sharp enough angles to draw blood and Katy Jarzebowski’s elegant yet earthy score adding to the intensity of the drama, “Clementine” sears itself into one’s memory even as Karen tries her best to avoid doing any such thing to Karen. After the film’s premiere at the Tribeca Film Festival, Gallagher spoke about the inspiration behind it, casting actresses who could bring their own experience to the parts and unexpectedly becoming an expert on federal land around lakes.

How did the film come about?

I was just really just interested in exploring female relationships and how it can feel like a sister dynamic or like rivals, or like a mother/daughter at times or even sexual in nature all the same time. It’s really something I haven’t seen in a lot of films, which seems just so intrinsic to what it means to be female and [as] something I haven’t seen, I wanted to see more of it.

I loved the idea that Karen finds herself in the position her former lover D was in terms of being older than Lana and seemingly in a position of authority. How did you want to play with that?

There were drafts where I was trying to write in scenes with the older character D character, and how to really get at that relationship. That’s not on screen, but it’s still so much a part of what she’s doing and how she’s acting, so I wanted that relationship to be this haunting presence that’s just there but not something that we’ll try and unpack who was wrong and who was right and what happened. I wasn’t interested in talking about that end of the relationship, but really what do you do when you’re dumped? Where do you take all of that? And how do you how do you learn from it, but maybe not take the bad parts? How can you take something that’s traumatic to you and use it? That’s also something that I was personally going through [with] a really bad breakup and wanting to be better for it, at the same time still just hurting and [asking myself] how to do that and how to put that into my work and and not let it bring me down. And I’m happy to say that I’m here at Tribeca, so I think it worked.

What was it like developing the relationship you do see between Sydney and Otmara as Karen and Lana?

I never met either of them in person, which thinking back on it now is just so crazy because it’s so much about their chemistry and physicality, even dealing with the age difference. Once we got them in the room together, things definitely changed and Sydney brought everything I was hoping for like this idea of how someone could could seem both mature and experienced and older yet also incredibly young and inexperienced and naive the same time. She just has that. Her eyes just do so much work. They were the characters in a lot of ways. Sydney is also from Spokane, Washington, so she has these Pacific Northwest roots and she just jumps in the water and Otmara, being from Miami, was very much like, “What is this place?” having never been to Oregon. She thought it was freezing the entire time, which actually really works for the character and where Karen was, being just skeptical the whole situation really. A fish out of water.

You come from the Pacific Northwest, right? Did you have this location in mind?

Actually, I’m originally from Pennsylvania, but I have been in Portland off and on for about 10 years, so it does feel like home and I think it was the East Coast sensibility when I was writing the script because I thought, “Oh, this is great. It’s mostly in this one location. I can just find one amazing place.” But it was actually incredibly difficult to find because most of the land around the lakes in Oregon is federal land, so it’s all protected and people don’t have houses on them whereas on the East Coast, there’s houses all around lakes. I actually grew up on a lake myself and there’s houses all around it. So it was really hard to find a house in a remote location, and we looked for about seven months in Oregon. We really lucked out with this incredible house and the family was so welcoming. They just gave us over the house entirely and they’ve been fans of the film. They’re actually here in New York to watch it, so it’s become a real family affair, which is [something] you can’t plan for. It’s just luck and sending out good vibes and just going for it.

The compositions are continually amazing and I understand you actually keep a couple wooden dolls in your pocket at all times to block out scenes…

Yeah, you can see on my website about 10 years ago, I made an animated short, but really it was just kind of these dioramas and I wrote stories with these sets. When I was storyboarding and shot listing, it really was just a quicker way to show blocking without having the actors there in advance and not being able to rehearse. I can’t draw. I wish I could, so as a way to print out what’s in my mind, it was just easier to show the characters as a really quick way for me to talk to my DP. I did paint them with their hair and it’s kind of weird, but it worked.

Did anything unexpected happen that’s in the film that you now really like about it?

The biggest unexpected thing was just I didn’t quite realize how physical the script that I wrote [was]. There’s the rowing of the boat. There’s breaking into the window. There’s the swimming and you just write these things not thinking, “Oh, we’re a small crew. We’re not going to have rehearsal or to have trainers” and then just expecting that to happen in a relatively quick amount of time. But Otmara was just an action star, so she just nailed all that stuff and was really up for it.

I also hadn’t done a shoot one of my own projects for longer than seven days with my Mac, so I actually really am happy to say I really really enjoyed [making a feature]. I didn’t know what’s going to happen to me on day 12. But I think it really suits the kind of storytelling that I want to do, just having the time and space to develop characters as opposed to like the shorts that I’ve done. where everything needs to be so tight and driving you to the next point. My background is in writing, so having that space to change things up or rewrite things in the moment or go back and add dialogue just really felt like how I want to work.

There’s an extraordinary moment in the film where the crackle of fire turns into drumsticks in the score. How did you work with the sound of this film?

The concept with the score was to really try and marry sound design and score and make the score really take cues from nature. I thought it would help us get into Karen’s head a little bit [since] again she’s not from the woods. This isn’t her house. This isn’t her environment. This is all very strange and surreal and haunting to her. So I worked with this amazing composer Katy Jarzebowski, who just taught me so much what she can do with instruments. We worked with the musicians to get that kind of human [quality] – the breaths and just even the little mistakes and unevenness of some of the things, and I think it really takes the film to another level.

What was the premiere like for you?

It was amazing. I was feeling kind of numb leading up to it, just like riding a wave and not realizing what it meant for it all to come together, but it was like a wedding. My parents were there and our actors and the woman who let us use her lake house. All of these all these people — it was just a giant blending and it was really exciting.

“Clementine” will screen once more at the Tribeca Film Festival on May 4th at 5:30 pm at the Regal Cinemas Battery Park.