The addiction-recovery mantra of taking it one day at a time is at the heart of this honest-feeling drama, a grownup debut from first-time London film-maker Thea Gajić. She has spoken in interviews about her father being the inspiration for this painfully believable character study, which gives us an alternative to movies portraying addiction as an issue to be tackled or put under a microscope.

Surviving Earth features a raw and powerful performance by Croatian actor Slavko Sobin. He plays Vlad, a handsome and charismatic recovering heroin addict living in Bristol, having arrived in the UK in the 1990s, fleeing the Yugoslav civil war. After years of using heroin, he’s now clean, working as drug counsellor and spending his evenings playing harmonica in a Balkan band with a couple of mates from work. Vlad has a grownup daughter called Maria (Olive Gray), who is an artist in London; she has complicated feelings about her dad – wary of being let down again by him again but craving his attention.

Vlad is a former soldier living with trauma, but what might undo his recovery is perhaps boredom and maybe a bit of delusion. He’s not satisfied jamming with his mates, supporting better-known local bands. He dreams big about putting on a headline gig, playing to an audience of hundreds. What Vlad seems to struggle with is ordinary life, the mundane everyday. With his fierce, energetic performance, Sobin carries the film. But Gajić’s script is too intelligent to present addiction as a battle against demons. Addiction is a terrible disease and with this mature, striking debut, Gajić hits her stride with confidence.

• Surviving Earth is in UK and Irish cinemas from 24 April.