It may mostly take place in the tranquil hills of the pacific northwest, but make no mistake: Leave No Trace is about the cost of war.We see that cost in the actions of Will (Ben Foster), a widower and vet whose PTSD drives him away from anyone other than his teenage daughter Tom (Thomasin Harcourt McKenzie). The film opens with the two living happily, but illegally, in the woods of a Portland state park, carefully covering their tracks and entering the city only when they need groceries or supplies. Although authorities eventually find and try to help to Will and Tom, they set the two off on a trip to find someplace where they can be left alone.Despite that description, Leave No Trace is no chase film. Outside of an annoyed fellow vet and a slightly insensitive police officer, everyone who Will and Tom encounters is gracious and polite. When Will asks a trucker give him and Tom a lift, the man pulls the girl aside and asks if she’s being held against her will. “I just need to know I’m doing the right thing,” he tells them, and that’s true of all the characters in the film. Whether they be an evangelical church group or a Washington mountain community, people repeatedly see Will as a man irrevocably damaged by war and do what they can to care for him.Working with cinematographer Michael McDonough, director Debra Granik (Down to the Bone, Winter\’s Bone) captures the full beauty of the forest landscapes Will and Tom travel. Although it never skips over the dangers they can present, Leave No Trace makes the woods look as warm and welcoming as the communities the duo inevitably leaves. The movie\’s quiet and elegiac tone focuses on the tiny moments of father and daughter gathering water or trying to get along with civilization.But as they adapt Peter Rock\’s novel My Abandonment, Granik and co-writer Anne Rosellini never let us forget what war has done to Will and, by extension, to Tom. Her devotion to Will centers the film, a girl who supports her father and accepts the way of life they’ve developed from herself. In the first act, we see her demonstrating to Will everything she’s learned, committing only minor (and completely reasonable) acts of rebellion when she insists on a faster method of cooking mushrooms for dinner. But as she\’s exposed to different ways of living, Tom realizes that she wants more for herself, and for her father, than the isolation he\’s been forced to seek.Granik gets remarkable performances from McKenzie and Foster, with the former perfectly playing an awkward but supportive teenager and the latter tamping down his sometimes overbearing mannerisms to portray a man who needs to escape society.The film\’s title captures Will\’s hope for his and Tom\’s life, to be unnoticed and unencumbered by others. But it also refers to the imposibility of that desire. Whether he wants it or not, Will and Tom keep coming across, and ultimately needing, other people, and these interactions make their mark on the family. More strikingly, there\’s the inescapable trace of war left on Will and continuing to Tom, a trace that even the movie\’s many gracious characters can\’t erase.