Fatalism, self-determination and imagination all gently wrestle for control of the narrative(s) in “Beach Fictions,” an enchanting and subtly profound diptych that follows one young woman through two diverging versions of the same day — saying much in the process about the voices, inner and otherwise, that we grant most control in our lives, for better or worse. Though its structuring principle of a single day playing out twice consecutively to differing effect (as opposed to braiding its alternate timelines like “Sliding Doors” or “Blind Chance”) explicitly recalls Hong Sangsoo’s “Right Now, Wrong Then,” this chicly poised debut feature by fellow South Korean Lim Hayeon has a style, tone and outlook of its own, maintained with impressive control over a surprisingly breezy-feeling 145 minutes.

One of the real discoveries in this year’s main competition at the Busan Film Festival, “Beach Fictions” should have little difficulty charming other programmers on the international fest circuit following its world premiere — while only its running time, manageable but unexpectedly robust for a film this light on its feet, presents an obstacle to global arthouse distribution, or at least specialist streaming exposure. Either way, this graduation project (produced by the Korean Academy of Film Arts) announces its writer-director-editor as one to watch, should her future films match this one’s warmth and formal elegance; in only her second big-screen outing after years of TV work, winsome lead Hansol Park also feels like a breakout talent.

“Beach Fictions” pulls you in from its first iridescent frame, as Sinuk Park’s camera glides serenely from a bejeweled nighttime view of Incheon through the chattery hubbub of a mood-lit restaurant where Tae-ju (Park), seen only from behind, is dining with friends, their conversation seemingly more animated than hers. Even without the detached voiceover — which turns out to belong to perceptive novelist Ewha (Sujeong Ye), describing the superficial response of Tae-ju’s friends to an anecdote she shares — we’d sense her loneliness amid company. Later, when her friends abandon her at the table to smoke outside, she’s crushed to find them gossiping about her; shortly afterwards, in a never-rains-but-pours development, she breaks up with her casual boyfriend Hyun-jin after he expresses scant interest in taking the relationship further.

With her social life in tatters and a world of her anxieties realized, Tae-ju rashly skips town, heading for the tranquil coastal guesthouse of another friend. On the train there, she encounters Ewha, whom we’ve already seen observing her from afar at the restaurant, and confides in the kindly, silver-haired older woman — who says Tae-ju resembles the protagonist of the novel she’s currently writing. But is she the writer’s inspiration or her creation, an incomplete fiction who has somehow taken on an agency of her own? From here on out, the authorship of Tae-ju’s life is ambiguous, as well as constantly in flux, buffeted by the whims and suggestions of others, as well as by her own impulses.

In the sleepy beach town, she meets and is immediately entranced by charismatic street magician Manhyuk (Kim Wookyum, delightful), only to later be warned off him by her hostess, who claims he’s a local lothario and sometime sex worker. A day in his company turns sour but when, in the film’s deftly shuffled second half, she meets him in slightly different circumstances, and the day’s events take on a different chain of connections, the potential romantic outcome differs too.

Her nascent relationship with Manhyuk is the chief variable of Tae-ju’s two stories, but other, slighter factors push it this way and that: a water-damaged phone in need of repair; a hangout with fellow guesthouse patrons that echoes or corrects her earlier social fallout; and a consultation with a psychic, recommended by Ehwa, whose counsel also shifts her fate. The contrasts between the two tales are never drastic; the gradations are sometimes as fine as those between warm and cool melancholy. The camerawork is consistently, richly sun-flooded, but some compositions isolate Tae-ju more than others; Wonhong Lee’s delicate jazz piano score can similarly tilt a situation from cozy to nervy.

But both gently lolloping narratives hold the attention, in large part thanks to Park’s deeply sympathetic performance as Hae-ju, simultaneously played as a fragile, will-o’-the-wisp go-alonger — or perhaps just an author’s as-yet-unformed blank canvas — and a wounded flesh-and-blood human now guarding her emotions more carefully. It’s a canny turn completely in synch with Lim’s complex, metatextual script, which brims with ideas about the fictional construction process, as well the real-life bind felt by vulnerable young women expected to bend to others’ desires and expectations. Is life itself not just a series of drafts and redrafts, with notes we either learn from or don’t, our characters never not in progress? Wry and wise and happy-sad, “Beach Fictions” crosses nothing out, alive to all possibilities.