It’s a generic title, and this brooding Australian indie sports drama itself feels a bit generic: you’ll probably guess the ending seven minutes into the movie. Still, it’s well-acted, particularly by Levi Miller who plays 15-year-old swimming prodigy Benjamin, known to everyone as “Boy” – a transcendent athlete gifted with Michael Phelps levels of talent. Miller impressively looks the part: strong legs, broad back, shoulders as wide as the Sydney Harbour Bridge. What’s more, he manages to bring a spark of personality to a character who for chunks of the movie is a super-focused obsessive swimming machine.

The film begins four months before the Olympics trials. Scouts from an elite sports institute in Brisbane are sniffing around; but then Boy’s dad Rob (Jason Isaacs) is released from prison – news that makes the front page of the local paper. Before jail, he was a violent alcoholic who terrorised his family; now he’s a spent force, broken and needy. From hereon in, the storyline acquires a slightly inevitable pull: Boy becomes distracted in the pool, drifting into trouble. He reconnects with his older half-brothers, a pair of heavily tattooed beer-drinking wrong ’uns. Can he turn it around before the trials?

The stakes are high. Boy’s mum repeatedly reminds him that swimming is his ticket out. For years she’s got up at 3am to drive him to practice. His coach says that he could be a national hero – or end up washing towels at the local sports centre. It’s an emotionally generous film: you don’t doubt that either of these adults love Boy. But aged 15, it’s as if he has ceased to be a child in their eyes – at the time when he needs support the most. I wondered too if first time writer-director Tyson Wade Johnston lets the men in Boy’s family off the hook a bit – explaining their toxic violence as dysfunction passing miserably, unstoppably down through generations.

• Streamline is available on 11 April on digital platforms.