TV writing legend Marti Noxon—of Buffy and Mad Men and Grey’s and UnREAL—makes her feature directorial debut with this personal, finely realized comedy-drama about a young woman grappling with anorexia. She’s Ellen, a smart, standoffish early twentysomething played with piercing credibility byLily Collins, who here reveals dimensions of her talent previously unseen. Ellen has been in and out of treatment facilities for most of her adolescence, and seems to be giving up the fight. But her chipper step-mother (a sympathetic Carrie Preston) has one last idea, sending Ellen to an alternative facility run by a kind, cool doctor played by Keanu Reeves. (I increasingly like Keanu Reeves as a doctor.) There, Ellen meets a range of broken—or at least hurting—souls, including a cute Brit named Luke, played with exceeding charm by Tony-winning young phenom Alex Sharp. Sharp makes his film debut along with Noxon, and he proves himself to the manner born. He and Collins have a sparkling rapport that works equally well romantically or platonically, a sharply rendered relationship that has quirky cinematic zest while still seeming genuine. But this is mostly Collins’s movie, and she holds it well, navigating a volatile, fragile emotional landscape with subtlety and insight. She’s perfectly in-step with Noxon’s filmmaking, which eschews the goop of easy sentiment, instead favoring a wry, weary frankness. Despite its harrowing subject matter, To the Bone is not some miserablist trek through body horror and despair. There is some of that, but for the most part Noxon’s engaging film is funny and humane. That’s no easy feat, but we probably shouldn’t have expected anything less from Marti Noxon. She’s a pro, after all.