SPOILER ALERT: This interview contains spoilers for “The Good One,” now in theaters.

“Good One” from first-time director India Donaldson is a light-hearted dramedy about three people on a backpacking trip. Until suddenly it’s not that way anymore.

Lily Collias, in her second leading role, plays 17-year-old Sam, who goes camping with her father Chris (James Le Gros) and his clumsy friend Matt (Danny McCarthy). After her father goes to bed, Sam has a clarifying conversation with Matt, who is going through a divorce, in a 13-minute campfire scene. At the end, Matt suggests that Sam come into his tent to warm up.

An hour into the film there is a disturbing and subtle twist, a moment of profound betrayal that presents a quiet, earth-shattering revelation to Collias’ face. What follows is an exploration of familial trust, flawed parents and the limits of forgiveness.

After its premiere at Sundance, Good One was acquired by Metrograph Pictures, the New York theater’s first acquisition, which is now expanding distribution. The film will hit theaters in LA and New York on August 9, with a wide release planned for the following weeks.

“People talk about seeing great films in the cinema, but I tend to think the opposite,” says Donaldson. “You can only experience the peace of an intimate film if you’re in the cinema.”

Donaldson talked to diversity before the theatrical release of “Good One” to discuss the process of making an indie film under adverse circumstances and to analyze the central scene.

Besides financing, what is the most difficult thing about making a debut film?

Hmm… I say, “Of course, the money.” Well, money is tied to gaining people’s trust, and if you’ve never made a feature film before, it’s even harder to gain people’s trust. For me, trusting myself is just as hard. I had so many moments of self-doubt along the way. To make a film, you have to keep going and block out that voice. For me, being vigilant to block out that voice was the hardest part.

“Good One” revolves around a pivotal moment between a teenager and her father’s friend. Is that where the idea for the film came from?

It’s hard to find the very first kernel. Ideas form in my head by things swirling around and then coming together in groups. I was interested in a character who is conditioned to please and serve others. I was interested in a teenager (protagonist). And I was interested in a subtle moment where the audience is betrayed by a character they have trusted.

I imagine this is the kind of film where when you’re writing the script you have no idea if it’s going to work. Because of the nature of the story, it relies a lot on the performances and capturing subtle moments in the characters’ faces.

I always knew the success of the film would depend on casting the right people. That came down to gut feeling, following my instincts about people and the potential for them to work together and with me. We also refined the form over time into its final form and part of that was the dialogue and the way the actors interpreted the characters. You discover things along the way as these great actors become the characters. The scene where Sam confronts her father, when I look back at my script, there is so much more dialogue than what ultimately ended up in the film. It was a much longer scene. I learned to leave out things that felt important in the scripting process that then become completely irrelevant when you see them on camera.

What did the filming of this scene look like in practice?

James Le Gros looked at the script and suddenly said some of the dialogue wasn’t necessary. Even more was cut in the editing, but he circled the line “Let’s just have a nice day” and said, “That’s the whole scene.” He was so right. Aside from what she said to him, that was the most important moment, and it immediately made me realize how irrelevant some of the more direct things he said were.

Although these films have essentially nothing else in common, “Good One” reminded me of the Peacock comedy “Please Don’t Destroy: The Treasure of Foggy Mountain” because both films take place almost entirely outdoors and both revolve around three people who go hiking. I interviewed Paul Brigantithe director of Foggy Mountain said that filming in the wild presented many unexpected challenges and that he had to contend with hornet nests, ticks, snakes and 100-degree heat. Did you encounter similar obstacles?

Paul and I need to start a support group for people who have shot movies outdoors. There was a constant threat that something would upset the tight schedule. We had no wiggle room. The actors were about to go on strike the day after we started shooting. We couldn’t lose a day because of the weather. One day we had a thunderstorm and couldn’t shoot. We shot what we could in the tents on the porch of the Airbnb we were staying in. We did our best to keep going at all costs, but I knew we had to adapt to whatever happened and I just hoped it wasn’t so massive that we had to cancel shooting. A little rain, a little thunderstorm, a little bear sighting – we were able to adapt in a way that narrowed our focus and made the process more specific. OK, it rained. It’s going to be wet in the scene and that gives it a kind of damp, sad quality that I think is absolutely crucial to the tone.

The film takes a turn when Matt hits on Sam after her father goes to bed, and basically invites his friend’s teenage daughter into his tent to keep him warm. How did you achieve the subtlety of this moment? A less confident filmmaker might have made this transgression more extreme.

I just go with what satisfies me. A more subtle moment reveals more complexity. A simpler, quieter moment reveals more layers and perspectives where a more aggressive note would have flattened the complexity or made Matt a more one-dimensional, malicious character. I adore this character. Whatever the audience thinks of him, I have sympathy for him. Part of the reason this scene comes so late in the film is because I want to give the audience a chance to get to know him and trust him and be disappointed in him, like Sam might be.

After this transgression, did you feel a responsibility as a filmmaker to maintain your compassion for Matt?

My sympathy for Matt and the way I portrayed his presence in the last third of the film is because we’re saying goodbye to him. He’s excluded from the story in a way, but really he’s excluding himself. He’s making himself smaller and more invisible, which is connected to his shame and all the feelings afterwards.

And then there’s the film’s bigger betrayal, which is Sam’s father’s indifference or unwillingness to confront Matt. This speaks to the character’s avoidance of conflict, but does it also speak to the broader idea that men tend to side with other men in these situations?

There’s a certain universality to the dynamic of the story that expands it. I just live in the specificity of these characters and this relationship. Thank you for saying that, that’s the bigger betrayal, because for me it is, too. The moment when you realize, “Oh, my parent is a flawed human being who is in denial of the truth in this moment, or can’t face this difficult thing that I’m saying – or doesn’t have the confidence to listen to me.” That’s more the broader theme I was touching on – the universal disappointment we all have with our parents at some point. It’s OK, our parents are only human, too, and I think as humans we rarely say the right thing in the moment. The way things play out in the movie, I imagine that 10 years from now, Sam and her dad might have a more productive conversation about the weekend, but on this day, that wasn’t supposed to happen.

How do you interpret the final moments of the film, when Sam’s father begs her to keep driving and gives her the car keys?

To me, there are multiple interpretations. He’s saying, “You drive. You’re in control.” It’s the peace offering. “Just take it. This is the best I can do.” But it’s also selfish. He’s tired. He’s been walking all day. He doesn’t really want to drive. It’s a convenient peace offering for him. It’s a peace offering on his own terms. It’s also just them in front and Matt in the back. It’s all of those things. It’s complex. He’s a person in that moment who knows he said the wrong thing and doesn’t know how to make it right. He’s grasping for a solution.

And she locks the two men out of the car for a moment and lets them wallow in their discomfort. But there is no major confrontation between them, just a heated argument.

In the short term, it’s easier to forget and push aside than to really live in conflict and face difficult things. One alternative I’ve imagined is that their friendship just fades and fizzles out and they lose touch but never talk about what happened.