There’s a moment in every childhood where kids find something out in the woods, whether it’s some discarded clothing, dirty magazines or, just maybe, an abandoned patrol vehicle. The latter transpires in Cop Car, the second feature from director Jon Watts (his first, horror movie Clown, will be released in the UK in February and is yet to be released in the US).

While wandering through the fields of rural Colorado, two eight-year-old boys, Travis (James Freedson-Jackson) and Harrison (Hays Wellford), happen upon an abandoned police cruiser with the keys still in it. They take it for an afternoon of joyriding, fiddling with the guns and playing with the yellow caution tape. Things take a sinister turn when they get involved with a crooked cop (Kevin Bacon) who left the car there to dispose of a body. He begins a game of cat-and-mouse, trying not to get caught as he tracks the boys down. The movie culminates in a tense, protracted standoff that keeps the audience on edge for way longer than is comfortable. I mean that as a compliment.

Bacon, sporting a creepy moustache, is great, and both boys give strong, naturalistic performances. Cop Car also marks Watts (who co-wrote the script with Christopher D Ford) as a director to watch – he has a spare, intimate style that uses awkward angles to draw out discomfort.

His film excels in its minimalism. There are only half a dozen characters and the plot doesn’t pile on needless complications; it lets the day play out slowly as the boys would experience it, getting more and more desperate. Watts and Ford give the audience just enough detail to let the audience figure things out, but not so much as to condescend, with Watts always keeping an eye on the emotional implications of what these kids are witnessing. In the end, it’s that simple intensity people will remember, where two boys have to act like adults before they’re ready.