Director Amma Asante’s handsome historical drama is a picture of social importance whose simplistic progressivism, however right-on, still unfortunately reads as 20-20 hindsight. The title character (Gugu Mbatha-Raw) is the biracial love child of a slave and a British naval officer (Matthew Goode), raised by a great uncle (Tom Wilkinson) who, as England’s highest-ranking judge, adjudicated a horrific turning-point case in slave-trade history. Misan Sagay’s script filters and alters these significant events into something like Guess Who’s Coming to Dinner crossed with Pride and Prejudice. The film pays careful attention to Belle’s complicated social standing — being, as she says, “too high in rank to dine with the servants, and too low to dine with my family” — but gets diverted by costume-drama spectacle and a faint confusion of storytelling priorities. At least as important as its protagonist’s self-possession and borderline-didactic eloquence is the young abolitionist (Sam Reid) who galvanizes Belle by challenging her conservative uncle and also falling in love with her. This all certainly is stirring stuff: Voices tremble, eyes moisten, and breath gets held in anticipation of characters doing the right thing. When they do, though, it just feels that much further away from how things are today.