The opening is hazy and easily forgotten as this unusual film drifts languidly along with not much happening, or so it seems.

Actor Maggie Gyllenhaal, writing and directing for the first time, uses close-ups and immersive shots of bodies half in and out of water to set the emotional tone of a woman, Leda (Olivia Colman), on a Greek island holiday on her own.

In a story based on an Elena Ferrante novel, Leda is confident and happy ­– yes, she’s a languages professor, she says with brisk assurance – and she has two girls, both in their early to mid 20s.

She likes solitude and resists intrusions, like the man looking after her apartment who wants to chat. She is happy with her reading and her thoughts.

At the beach one day there is a disruption she cannot avoid when a boisterous, beautiful and entitled family descends with all their attendant paraphernalia.

They take up so much space they ask her to move further along the beach but she politely declines.

It’s all a bit awkward, as are a lot of exchanges in this film which cleverly capture the social dynamics of concealed meaning and hidden feelings.

But there is a rapprochement and Leda gets used to them, especially the young mother Nina (Dakota Johnson) and her toddler daughter whose interactions she starts to watch.

The demands of motherhood are clear, and not always welcome.

We begin to understand through flashbacks that Leda has a messy story that she hides beneath the bright exchanges of information about her daughters and how well they are doing.

She doesn’t remember much about it, she tells the pregnant mother who asks how she felt raising her girls.

On the beach something happens, not a big thing but enough to trigger events that grow stranger and more complicated until we are deep in an intimate psychological unravelling that was as unexpected as it is engaging.

The film has won awards for Gyllenhaal and she deserves them for the script and the performances she draws from her cast: Colman is ever the bright beam of intelligence who conveys so much with so little, Johnston is glorious, and Jessie Buckley is compelling as Leda’s younger self, the gifted scholar of languages unsure of what she wants.

But Gyllenhaal’s mastery lies in the way she deftly layers the atmosphere like a painter until she has captured you in a web of social intrigue that you barely saw coming.

The Lost Daughter is now screening at selected cinemas, and on Netflix from December 31.