Return to Seoul is never quite what you expect. For starters, the poignant feature, the third by the Cambodian-French writer-director Davy Chou, concerns a 25-year-old woman, Frédérique Benoît (Ji-Min Park), who has never considered Korea to be her home. Raised in France by adopted parents, Freddie, as she prefers to be named, is only in Seoul after a planned flight to Japan goes awry; once there, she spontaneously decides to search for her biological mother and father, much like you might hunt down a novelty restaurant on a weekend getaway.

The thing is, Freddie, a moody misanthrope with an active social life, isn’t sentimental, nor does she wish to please her new Korean acquaintances. Whereas movies have taught us that family reunions are warm, sickly hugs backed by orchestral strings or a Dido ballad, Return to Seoul depicts stilted, awkward interactions that require an interpreter who punches up Freddie’s cold exchanges. Even worse, harsh silences fill the room.

“People look for meaning and closure in adoption stories,” says Chou, 39, in London, the week Return to Seoul hits cinemas. “But a happy ending can be dangerous if you believe too strongly in it. If you experience a shock in real life, the brutality then feels like a door going into your head.”

At quick glance, it’s apparent why Chou would make Return to Seoul his follow-up to 2016’s Diamond Island. After a childhood in France, Chou didn’t visit Cambodia until he was an adult, an experience mirrored by Freddie as she’s guided around Seoul with the assistance of a bilingual hotel clerk, Tena (Guka Han). However, the sullen protagonist’s arc more closely resembles the life of Chou’s friend Laure Badufle, a Korean-French adoptee who’s credited as a “script consultant” (or “the inspiration”, per her Instagram bio).

When Badufle first encountered her biological father in Seoul in 2011, Chou was effectively her Tena: he offered emotional support and translated between French and Korean. “In documentaries, films, and TV reports, meeting the parents is when the puzzle is finally complete and you feel at peace with yourself,” says Chou. “But Laure insisted so many times: ‘When I met my father, that’s when all the trouble started.’”

If Return to Seoul seems to zig when you anticipate a zag, it’s because life itself is unpredictable. Although Freddie is at one point a booze-loving, partying goth, she’s later employed by a weapons manufacturer, much like Badufle was in her early 30s. However, Sight & Sound magazine, in an otherwise rave, deemed the arms dealing career choice “too blunt a metaphor”.

“I read that, too,” says Chou with a laugh. “It’s interesting because we also watch genre films with…” He trails off. “Anyway, that’s not the point. It not only follows the real life of my friend, but Freddie is a character who’ll jump into an unstable zone just to see what the consequences will be. I wanted to follow the extremities of where she would go, and still accompany her. I understand if it’s completely shocking for the audience.”

Likewise, Return to Seoul boasts an atypical film structure that reflects Freddie’s spontaneity. Spanning eight years, the drama loosely maintains a three-act structure but one in which the middle section is 20 minutes long, and the time jumps are as surprising as jump scares. Initially, Chou even toyed with only shooting mealtime scenes. “No other elements. Just dinners and lunches for years, and you’d see the evolutions. Maybe I was too influenced by Hong Sang-soo.”

For the eventual script, Chou settled upon what he refers to as ellipses between acts and “the vertigo of what happened in between”. Drafts were sent to Claire Denis, whom Chou met when she had a retrospective in Cambodia (“she’s a filmmaker I absolutely respect and love who’s shot in Korea”), while a balance was struck between subverting cliches and chucking in grenades (not necessarily the ones Freddie eventually sells) for the sake of it. “If you’re too surprising, you’re like, ‘It’s just a script.’ It has to emotionally make sense.”

He continues, “Each part has a beginning and end. In part two, it’s not in the dialogue, but she understands it’s time to go back to France. She’s trying to prove to herself that the life that was stolen from her – to be a Korean girl – she can decide to live that Korean life, to have a boyfriend there, to have Korean friends, to have a job there, all without any help from her Korean family. But what for? She understands it’s the end of that experiment.”

Early on in Seoul, Freddie, who considers herself French, finds that the locals wish to mould her into their cultural template. Freddie’s alcoholic father (Oh Kwang-rok) insists she belongs in Korea, where he will help her marry a Korean man (Freddie’s eye roll is so hefty, it requires big-screen viewing); a one-night stand with an introverted local leads to a romantic proposal that provokes callous laughter, not a swoon.

Freddie, too, was intended to fit a different persona for Chou who originally wrote the character’s mid-film era as a miniskirt-wearing male fantasy that Park refused to embody. A visual artist making her acting debut, Park instead insisted that Freddie could be more like, amongst other references, Furiosa from Mad Max: Fury Road.

“A friend told me that I should meet her because she matched Freddie’s personality. Usually with first-time actors, you play with the character and ask the actors to be themselves. But Freddie reinvents herself, so there’s composition. She’s always switching emotions inside the same scene, or sometimes the same shot. I was scared it would be hard for her, but she revealed herself to be a natural.”

In the screenplay, Freddie was supposed to tell a boyfriend towards the end, “I need you to protect me.” After Park protested, the line was altered to “I will need you.” Chou comments, “Now I understand. By changing this little detail, it brings another layer of maturity to the character.”

When Return to Seoul premiered at Cannes, its English title was All the People I’ll Never Be, referencing Freddie’s confusion between cultures. A year on, Chou is still taken aback by the number of personal anecdotes he receives after screenings across the world. “There’s an obsession with identity on the conservatist spectrum with national identities blah blah blah, but also on the progressive spectrum with sexual identities, subcategories, and people being able to define themselves. But what happens to people who feel they don’t belong in one box? That’s where Freddie finds resonance with people.”

After all, if you return to the soul of Return to Seoul, a rewatch reveals that Freddie’s body language often contradicts her dialogue. “She’s always in advance of the audience,” says Chou. “You think you understand her, but she’s already transformed herself.”

Return to Seoul is out in UK cinemas now