A sense of doom hangs over Charlotte Wells’s superb Aftersun. Eleven-year-old Sophie (Frankie Corio, naturalistic and charming) and her dad, Calum (Paul Mescal), are on a longish holiday at a sun-drenched Turkish resort. It’s not quite idyllic–there’s construction going on, and the hotel messes up their booking for a two-bed room, forcing Calum to spend his vacation on a narrow cot–but in a lot of ways, it’s close enough, at least for Sophie. It’s gorgeous and full of lazy fun; Sophie and Calum have a great rapport, with a delicately portrayed father-daughter relationship that encompasses both playfulness and sincerity, and they obviously love each other and get on very well. But thanks to elliptical flash-forwards and the wistfulness of the title, you can sense the presence of a shadow.

Intermittently, the movie toys with you, giving you scenarios that seem ripe for dramatic and even pulpy turns for the worse, but everything generally works out fine. Threats shimmering on the horizon turn out to be mirages. And, gradually or quickly, you start to understand that the steadily darkening shadow here has nothing to do with any kind of malice or carelessness or, in fact, conventional danger at all.

It’s just that Calum is drowning. Paul Mescal gives a subtle and nuanced performance as a man in a deep depression, a loving father constantly pushing himself to be there for his daughter and not let her know that anything’s wrong. He’s trying so hard, digging his fingernails into an unforgiving cliff to try to stop himself from falling, and more and more, we catch the moments when that hold slips. He can pull himself together for Sophie, but when she’s not there–sometimes even when she looks away–the exhausted, blanked-out sadness seeps back in. Towards the end of their trip, he unravels more and more, even as he continues to fight against it.

In the present day, an adult Sophie (Celia Rowlson-Hall), seen mostly in brief flashes, is now a parent herself, potentially struggling too. She keeps looking back on this holiday, combing through memories and fleeting bits of footage, going back through what she was once too young to understand. She’s haunted by frenetic visions of her and her dad in a crowded club, separated by the throng, and there’s the elusive feeling that if she can only just reach him, it will be okay. They’ll be okay. Even thinking about how the film finally deals with that question makes me cry.

Aftersun is streaming on Showtime.