I see you, dad: Tom (Thomasin McKenzie) and Will (Ben Foster) in Leave No Trace. Photograph courtesy Imdb.com

FROM THE VERY first spider web exquisitely filmed cast against the light, you understand some of the basic premises of this story. From the first moment you see Tom (Thomasin McKenzie), a young teenager living with her dad, Will (Ben Foster) in the great outdoors, you understand that this is no lark, camping holiday or environmentally ideological stance. It’s an essay on the horrors of PTSD and how this world continues to cannibalise its young men.

Premised on the detritus of war – the Afghan war, in this case – the work engages with the emotional brokenness left in its wake. And there are no sensational flashbacks into a crude understanding of the kind of horror this young father experienced – as you may have seen in films such as Goodbye Christopher Robin or Rebel in the Rye – rather, the director points your gaze towards the way in which Will must live in order to survive.

It’s a devastating, yet deeply empathetic and wisely balanced view of contemporary homeless society in America: the people who have fallen off the grid and out of reach for whatever reason. But more than that, it’s a deeply evolved and intimately honed understanding of where the child of such a man can be – emotionally, developmentally, individually. With an utterly searing debut performance by McKenzie the work touches on the moment when a child is forced to take the lead. When the child takes possession of herself and understands her earnest sense of responsibility which supersedes that of her carer. When the child understands what happens next. When the child puts away the sea horse fantasies, the toy horses, bees and bunnies because this is no drill.

This film echoes the type of values so eloquently articulated in the David Williamson play Odd Man Out, on at Auto and General Theatre on the Square, at the moment. The texture and complexity of mental illness cast against a society of normalcy. Above all, it’s a yarn where you get to understand the overwhelming value of kindness in this world.

• Leave no trace is directed by Debra Granik, based on the novel My Abandonment by Peter Rock. It features a cast headed by Marisa Anderson, Derek Carmon, Dale Dickey, Zoë Dotson, Michael Draper, Derek John Drescher, Ben Foster, Spencer S. Hanley, Art Hickman, Michael Hurley, Jacob Johnson, Ryan Joiner, Jeff Kober, Susan Chernak McElroy, Erik McGlothlin, Alyssa McKay, Thomasin McKenzie, Dana Millican, David M. Pittman, Michael J. Prosser, Jeffery Rifflard, Peter Simpson, Isaiah Stone, Bob Werfelman and Tamera Westlake. It is written by Debra Granik and Anne Rosellini. Produced by Anne Harrison, Linda Reisman and Anne Rosellini, it features creative input by Dickon Hinchliffe (music), Michael McDonough (cinematography), Jane Rizzo (editing), Kerry Barden (casting), Chad Keith (production design) and Erin Aldridge Orr (costumes). Release date, through Cinema Nouveau, Ster Kinekor: September 21 2018.