The story goes that Brooklyn filmmaker Keith Miller took his newly adopted dog for a walk one night and wound up arguing with a stranger, Shannon Harper, who claimed the dog was actually his. Both men noticed their differences—for starters, Miller is white and Harper is black—and both noticed how they each really seemed to love the dog. Miller returned the next day, asking Harper if he’d care to reenact the episode for the purposes of a movie. They did, and now it’s the prologue in this intimate, movingly imperfect fact-fiction hybrid. Harper portrays someone like himself, a former drug dealer now working as an insurance adjustor, and Miller takes just enough creative license to afflict his protagonist with the same rare cancer that actually killed a friend to whom the film is dedicated. Welcome to Pine Hill considers the modern dynamics of class and race, but mostly seems designed to feel like life. Predicated on Miller’s receptiveness to magical heightened-reality moments, it sometimes loses nerve and nudges them along against their will: At times the improvised dialogue seems too schematic and superfluous, especially in view of such exploratory and observant handheld camera work. Otherwise, though, this is wonderful stuff. In Miller’s moviemaking scheme, Harper not being or seeming like an actor is not a problem; it’s a solution. The film seems to power itself just by knowing it could not exist without him.