Del Kathryn Barton is an Australian artist who regularly enters and twice won the Archibald Prize, once for a portrait of Hugo Weaving. The Art Gallery of South Australia has also presented her work – including a short surrealist film featuring actor Cate Blanchett that was inspired by the sexual cannibalism of the redback spider. Barton is not known as a filmmaker but her style – which is ornate, whimsical and offbeat – is a good indication of what to expect from an impressionistic film that deals in essences rather than story.

Walking home one day along a distinctively Sydney street, 12-year-old Blaze (Julia Savage) is the horrified eyewitness to a laneway encounter that erupts violently into rape and murder. Mute with shock, Blaze watches but does nothing, meeting the panicked eyes of the woman (Yael Stone) before she dies. The man tidies up and leaves.

Blaze returns to the terrace she shares with her father Luke (Simon Baker), a warm and loving single dad who realises pretty quickly that something is up. After hearing what happened, he does the right thing and takes her to the authorities who funnel Blaze into a system of health checks, police statements and perfunctory psychological counselling. He shields her as much as he can but the system is broken.

These are the bones of a plot that at its heart follows Blaze having to grow up. She is a gentle girl on the cusp of early womanhood who has a powerful imaginary life and she is lost within such a turbulent and terrifying event. At home, she retreats into fantasy, where the dragon Zephyr is her friend and strength.

Giving evidence in court, though, things are different. Blaze is asked repeatedly why she didn’t intervene and do something – it’s a question she can’t answer herself – and whether she is sure of what she saw. The man is sitting there and she blasts him with her fiery dragon’s breath but in the cold reality of the justice system, nothing happens.

This internal battle plays out on screen in ways that give Barton free rein to pursue her art through a mashup of VFX, live action, puppetry and animation. We see fantastical creatures, blinking doll faces, butterfly eye masks, figures popping out of heads on ladders then scurrying back down as Blaze’s battle between reality and fantasy, childhood and the adult world, plays out.

As she continues to run off the rails, the despairing Luke seeks help. Blaze is counselled by an open-hearted, gloriously witchy woman who shows the young girl there is hope ahead.

The film becomes something of a feminist anthem, with Blaze surrounded by a ghostly force of shadowy women for whom this story is painful and real. In fact, a story in a newspaper about sexual assault inspired Barton to put it on screen.

Patience is required to give Blaze the space it needs to breathe and blossom into something unusual and worthwhile. The beautiful performance from Julia Savage as Blaze is a source of joy, buoyed by the warmth and sanity of Simon Baker as a father at his wit’s end. It is steeped in Barton’s trippy aesthetic and sits proudly as a visual imagining of a young woman stepping out of childhood and into her power.

Blaze is in cinemas from Thursday.