The debut feature of Scottish director Charlotte Wells is a meditation on memory, a woman selectively remembering a vacation with her father from twenty years before, sifting for clues about what she might have missed.

“Aftersun” gives us only a couple of glimpses of the grown Sophie (Celia Rowlson-Hall), first in a strobed nightclub-lighting edit in the middle of a piece of home movie footage from that trip, which Dad (Paul Mescal, just seen in “God’s Creatures,” previously in “The Lost Daughter”) recorded on his camcorder. Later, Sophie recreates some of what her father was videoing, as if she’s reached some sort of conclusion about the long Turkish idyll she took with him just after she turned 11, a trip in which he turned 31.

In between, we experience something resembling her incomplete memories of that school break trip, a cute, curious kid (Frankie Corio) who took in some details — how the older kids in the hotel, arcade, pool and beach where they were staying spoke (slang), behaved and flirted — and missed others.

It’s a film of disarming routine focusing on a doting-not-hovering Dad who is plainly making an effort. He’s not with her mother, and not even in the same town anymore. He’s in London, she’s back where he grew up, Edinburgh. He still says “Love you” to Sophie’s mum when she calls to check in on them, which confuses her.

And when Sophie gets the camera, it’s interview time.

“When you were 11, what did you think you’d be doing now?” It’s not a question he answers directly.

She asks him how he broke his wrist (it’s in a cast), as if the adult Sophie has forgotten that detail and needs to remember. She notes his smoking, his solitary moments, his Dad version of tai chi, asks about changes in his work and relationships, and gets distracted by the older kids he lets her hang out with.

Because Dad is distracted, too. Whatever face he’s putting on for this trip, there’s a deflating despair in his unguarded moments. She remembers him being short of cash but not chewing her out for losing her diving goggles. He leaves her on her own more than seems natural today, and in situations that could be potentially dangerous.

Wells set out to tell a story with little in the way of incidents and melodrama, a movie that weaves its spell in observations, snippets of dialogue a child might not have understood then but have resonance for the adult Sophie, experiencing parenting in a same sex relationship at 31.

Overhearing Dad tell a dive boat instructor, who “can’t see myself at 40” doing this job, that he’s “surprised I made it to 30,” was something she might have picked up on, had she not been 11.

The strobing of hotel nightclub lighting becomes a metaphor for memory here, the pixelated edits of old video emblematic of Sophie summoning up snatches of uninformative background noise and the occasional piercing moment of consequence in watching the old videos and casting her memory back to her eleventh year.

Wells tests the viewer by limiting the scope of what we’re seeing, keeping things on a near mesmerizing level by not giving us more big emotions, big revelations or big scenes. It works, although it frankly could have come to the viewer a bit with more of the adult Sophie, letting us see what she’s figuring out. “Aftersun” is unnecessarily obscure and overdoes the whole “understated/unstated” thing.

Mescal gives a subdued performance that draws us in, as we’re forced to focus on him and ponder what insights about this pivotal moment in Sophie’s childhood we might glean from what she remembers of him. Corio is properly unaffecting, showing little hint of the “child wise beyond her years” cliche so common in Hollywood films.

Whatever’s coming, she’s just a kid. How could she have known? Whatever happened, how could she have changed it? That’s the cruel trap of memory, protecting us, then hitting us with revelations long past the point they’d do anybody any good.

Rating: R for some language and brief sexual material.

Cast: Paul Mescal, Frankie Corio and Celia Rowlson-Hall

Credits: Scripted and directed by Charlotte Wells. An A24 release

Running time: 1:40