A teenage girl (Agnes Bruckner), wounded by her parents’ ugly divorce, turns to her high-school English teacher (David Strathairn) for encouragement, and he urges her to “go deeper” with her poetry. Writer and director Karen Moncrieff has crafted an observant little gem that offers no easy answers and paints no real villains. It’s not perfect: A subplot with the girl’s younger sister (Regan Arnold) is overloaded with symbolism, and the character herself speaks in self-consciously poetic aphorisms. But the film’s virtues far outweigh that quibble. Bruckner and Strathairn give delicately nuanced performances (we expect it from him; she’s a welcome newcomer). We can see the mistakes and wrong turns they’re making, and the knowledge of what must be coming makes it painful to watch, yet it never sinks to become melodrama.