Tom (Thomasin Harcourt McKenzie) is a teenage girl who lives with her veteran father, Will (Ben Foster) in a large park near Portland, Oregon. Will and Tom sleep in a tent, harvest rainwater and eat wild mushrooms: they are homeless, whether by design or default. Their camp is isolated, but even so, wary of someone finding them, they run drills, scrambling off into the forest to hide in the ferns. They take trips into Portland for groceries and for Will to visit the veterans' hospital.
Will and Tom's life is different and difficult. But Tom appears relatively happy and carefree and clearly loves her father. Will has schooled Tom: she can read, write and even play chess. Will's obviously fighting some demons, but he is intent on raising his daughter, albeit in an unorthodox manner.
But life in the park comes to an abrupt end when an errant jogger spots Tom. The police detain Will and Tom and turn them over to social services. The situation is confusing for authorities: no real laws have been broken, but living on state property is forbidden. Will and Tom are given psychological tests. Tom is actually ahead of where she needs to be academically, although as the caseworker explains, she needs socialising skills and should be in formal education. Will is also revealed to be competent enough to look after his daughter - he just needs to find a proper home for her.
A solution comes by way of a good samaritan, who will house Will and Tom in a cabin on his farm, in return for Will pitching in with the work. Will begrudgingly accepts and for a while, an uneasy lull prevails. At the farm, Tom rescues a stray rabbit that belongs to a boy her age and they strike up a prelude to a friendship.
Will and Tom gradually take footsteps into normal society, but Will becomes restless. Meanwhile, Tom is starting to think that stable accommodation and meeting others her own age might be something she would like. Tom slowly realises that this goes up against her father's wishes and that for him, moving around and living on the margins is all he can do.
Directed by Debra Granik, known for the acclaimed Winter's Bone, Leave No Trace was adapted from a book by Peter Rock. The story of Will and Tom's strange and marginal existence is told vividly and deftly. Backstories are few: Will is a veteran of an unidentified conflict. Also, Tom's mother is dead, but when and how remains unsaid. Will and Tom have lived in the park for a while and have moved camps in the past.
We also know that Tom is bright, accepting and fairly happy with her life. But it's not long into the film that we sense the stirring of change in Tom. She stumbles upon a lost necklace on a trail and asks Will if she can keep it. It's the first sign that underneath it all, Tom is a teenage girl, and she might want the same things other teenage girls want. Later in the film, when Will decides they must arbitrarily leave comfortable housing, she tells her father that she likes it where they are. Tom is changing, and growing up.
The film benefits from outstanding performances. Ben Foster's Will is pitch-perfect, showing a man haunted by war but determined to fight on. Thomasin Harcourt McKenzie as Tom is also flawless, as we watch her begin to question her existence, all while we are reminded at every step about how much Will and Tom love each other.
Leave No Trace is compelling and assured storytelling with an end result that is moving and very touching. Go and see it.