After disturbing us all with survivalist thriller It Comes at Night in 2017, Texan film-maker Trey Edward Shults – still just 31 – steps up his already impressive game with this vehemently acted and formally audacious drama about an African American family in Miami. It is a parable of redemption, and about a kind of spiritual or metaphysical resonance between the unhappy lives of two siblings.

At film festivals worldwide, Waves has already been much praised for an experimental, anti-narrative approach and a supposed privileging of vignettes, scenes and moods over regular storytelling. Actually, this is misleading. The movie is perfectly legible in conventional linear terms. But where it goes, how it gets there and how it comes back again, is more unexpected. There is a wonderful score by Trent Reznor and Atticus Ross.

Waves has flaws. Some of the emotional transitions are maybe a little forced and Shults, a former crew-member on Terrence Malick films, maybe gets a little too Malickian occasionally. There is only so much value in ambient shots of people putting their hands out of the window of a moving car and dreamily undulating their palms in the rushing wind. The other movie it clearly resembles is Barry Jenkins’s Moonlight and, although not quite as ambitious, Waves is intelligent and heartfelt in a comparable way.

Tyler is an outstanding young high-school student, self-consciously poised for greatness at college and currently a thrustingly aspirational star of the school’s wrestling team, presided over by a fanatical and shouty coach who makes them all chant in unison: “I cannot be taken down! I am a new machine!” The cult creepiness of all this, combined with Tyler’s not-so-subtle air of being pleased with himself, is disquieting.

He is played by Kelvin Harrison Jr, combining an air of calmly submissive worthiness with a hint of something destructive and bottled up, rather as he did with a similar high-school role in the movie Luce. Tyler is forever addressing throwaway greetings over his shoulder at his parents as he arrives home at the end of a school day, trotting upstairs to his bedroom to do his homework or jerk off to porn. He is dating beautiful fellow student Alexis (Alexa Demie) and their relationship is in still in the state of euphoric infatuation. Yet how well do they really know each other?

For the present, Tyler’s real problem is his impossibly demanding and overbearing dad Ronald: a fierce performance from Sterling K Brown. Ronald requires absolute commitment from his son in everything (while ignoring his daughter) and insisting with tragic absurdity on training with him, even challenging him to an arm-wrestling match at a family supper when Tyler presumes to mock his dad. (Maybe he is a little like Robert Duvall’s gruesome basketball-playing father in The Great Santini.)

Trouble ahead … Kelvin Harrison Jr as Tyler and Sterling K Brown as his dad in Waves. Photograph: A24

Ronald is married to Catherine (Renée Elise Goldsberry) who is the counterbalancing carer in this family, all too aware that star-student golden boy Tyler is sucking the attention oxygen away from his quiet, smart, shy sister Emily (a lovely performance from Taylor Russell). But there is serious trouble ahead. Ronald uses opioids to manage residual pain from an injured knee, and Tyler is in the habit of stealing these from the bathroom cabinet to medicate his own worryingly painful shoulder. The film shows that he has inherited denial, an intensified and less manageable state of denial than the one Ronald is used to, but – rather terrifyingly – he has been made aware of his own fragility and even mortality in a way that his middle-aged elders have learned to ignore.

When Alexis sends him a disturbing text, Tyler’s life spins out of control, generating a parallel drama in the life of Emily, who is to find a connection with classmate Luke (Lucas Hedges), who we last saw getting beaten at wrestling with rule-breaking violence by Tyler. Whatever agonies Emily is suffering on Tyler’s account are being salved by her relationship with Luke, and Shults shows that Emily’s story has a kind of mysterious spiritual equivalence to Tyler’s. She acts out the workings of some secular form of divine grace.

There are big scenes, big performances, big emotions here, and audiences will have to recalibrate their antennae for these, especially for the stunning shock that arrives around halfway through. The waves of emotion can get very high, yet they bring exaltation with them.

• Waves is released in the UK on 17 January.