En England in the 18th century, Dido Elizabeth Belle, a mixed-race woman, the illegitimate daughter of an admiral in the royal navy, was brought up by her aristocratic great-uncle, Lord Mansfield. She enjoys certain privileges. But, the color of her skin prohibits her from participating in the usual activities of a girl of her rank. She falls in love with a lawyer who dreams of changing the world. Both will end slavery in the country.