Race and slavery aren’t the sort of themes you’d expect in an 18th-century period drama set in London. Nevertheless, in Amma Asante’s Belle, the award-winning British director explores the ethics and horrors of slavery interwoven with familiar Jane Austen premises like social mobility, women’s standing in society, love and the business of marriage.

What sets Belle (based on a true story) apart from the staple of costume dramas we’re accustomed to isn’t the film’s spotlight on the slave trade, but its biracial, African and English aristocratic female protagonist, Dido Elizabeth Belle, who quietly contributed to the abolition of slavery in Britain.

RELATED: WATCH EXCLUSIVE CLIP FROM ‘BELLE’ [VIDEO]

Despite being an influential figure in British history, very little is known about Belle (portrayed by English actress Gugu Mbatha-Raw). Director Amma Asante and Belle screenwriter Misan Sagay (Their Eyes Were Watching God) discovered Dido in a striking 1778 painting that defied everything they believed to be true of Blacks in the 1700s in England. Aristocratic European paintings seldom depicted Blacks in a favorable light, if they were featured at all. People of color were often positioned in the background looking up at the towering Whites with adulation, while reaching out to touch them to underscore the key subjects’ high status.

Dido Elizabeth Belle’s portraiture broke every rule.

Featured alongside an elegantly dressed White woman, Belle stands at the center of the frame gazing straight, clothed in an ensemble indicative of her noble footing: a luxurious silk and satin gown with a single strand of pearls adorning her neck, and a turban with an ostrich feather. Although her seated White companion (who in this instance is the one tenderly reaching out to touch Belle) is pictured in the foreground, Belle’s playful expression, confident smile and lovely dimple draws eyes to her, and keeps them there.

Belle is the narrative behind this arresting portrait.

The film opens up with Belle’s father—Admiral Sir John Lindsay of the Royal Navy—taking a 7-year-old Belle to live with her great-uncle, Britain’s most powerful judge William Murray, the Lord Chief Justice of England and the Earl of Mansfield, following the death of her enslaved African mother, known only as Belle.

Upon their first introduction, Lord Mansfield and his wife are taken aback by Dido Belle’s Black skin (“a detail you chose not to share with us!”). But the childless couple, also raising another nephew’s daughter (Lady Elizabeth Murray), takes her in as their own. She develops a close and loving paternal relationship with Lord Mansfield and a sisterly bond with her half-cousin Elizabeth, who is the woman ultimately featured in the painting beside Belle.

While Belle’s birthright affords her a privileged life and an education she’d never have been privy to as a slave, her life at the Mansfield estate isn’t without its harsh realities. She isn’t allowed to join the family for formal dinners, but gets invited to join them after supper, where guests are astonished to see her. “How can I be too highborn to eat with the servants, but too low to eat with my family?” she questions, perplexed.

When it comes to marriage, Belle is too Black to marry a man of her social rank and too high on the social ladder to even consider a poor Black or White man. Ironically, she eventually inherits a large sum of money from her father following his death, enough wealth to ensure she doesn’t need to marry for finance. In contrast, her half-cousin Elizabeth doesn’t have the same fortune, and desperately searches for a possible suitor to secure her own future.

Money trumps race as we witness White suitors courting Dido Belle in hopes of getting their paws on her money, leaving her struggling to discover where she fits in this aristocrat world as both a woman and a woman of color.

Dido’s journey to self-discovery is heightened by a legal case brought before Lord Mansfield. The 1781 Zong massacre—in which enslaved Africans being transported to England were thrown overboard by the crew in hopes of collecting insurance money for their damaged cargo—was a defining moment for the country and for Dido Belle. Not only does the case awaken her political awareness (dormant for years thanks to her sheltered life). The massacre also introduces her to an abolitionist lawyer, John Davinier, who helps Belle persuade to her great-uncle to rule that Blacks are human beings and not disposable cargo, thus leading to the emancipation of 14,000 slaves.

Belle is a layered, timeless coming-of-age tale that raises questions about class, gender and race, but its most prevailing thread love: the love Belle shares with Mansfield; the love between her and Elizabeth; the love that blooms with Davinier; and most importantly, the love she develops for herself as a woman of color.

While Dido Belle’s life is a radical subject for a period film, Belle—despite a poised star turn from Gugu Mbatha-Raw—sadly falls victim to formulaic Hollywoodish storytelling that’s a bit too predictable for such a complex story. The painting that inspired the film, which now hangs in Scone Palace in Scotland, packs a much more urgent punch than the film itself.

Just the same, the movie adds some much needed race consciousness and diversity to a genre that’s all but rendered a woman like Dido Elizabeth Belle invisible.