For decades Kent Jones has been one of the most eloquent and perceptive film critics in the U.S.; with this devastating chamber drama (his first narrative feature as writer-director), he also proves himself to be a keen observer of psychology and American social mores. Mary Kay Place, in a heartbreaking performance, plays the title character, a single, 60ish woman in upstate New York who devotes herself to helping the homeless and the terminally ill but can’t help her resentful grown son beat his addiction to drugs. Jones doesn’t exploit the scenario for simple dramatic irony—Diane is no saint, and her son is to some extent justified in his resentment of her—nor does he steer the story toward predictable emotional payoffs. What he wants to explore is ultimately harder to define—call it the longing for transcendence that’s always underpinned American life. His handling of time’s passing is subtle and mysterious as well.