By turns tender-hearted and heavy-hearted, director Drake Doremus’ spartan romance delineates the wrenching vicissitudes of first love as a long-distance relationship. Felicity Jones and Anton Yelchin play two sensitive college students of different nationalities who find their prospects confounded both by immigration logistics and by having their whole lives ahead of them. Co-scripting with Ben York Jones, who also appears in a tiny supporting role, Doremus reportedly also encouraged his game and gifted actors to improvise; they rise to that challenge, honing the story by hewing to its barest essentials. Doremus also has a knack for the emotion-stoking transition, be it a courtship montage or a time-lapse dissolve through which the lovers fade in and out of each other’s spaces. The final result, though slight, seems like an essential movie love story, reveling not just in the headlong thrill but also in the true companionship of accumulated mutual history. Charlie Bewley and Jennifer Lawrence co-star, graciously.