Nang Tard (2008)

Yen was sold to be a slave to Khun Ying, Praya Sihayotin's first wife. Praya Sihayotin had 3 wives, but none had children, so he took Yen to be his fourth wife, with the blessing of Khun Ying. Yen became pregnant, and soon after, so did Khun Ying. While Praya Sihayotin was away, they both gave birth, but Khun Ying's infant boy was stillborn, so they agreed to secretly give Yen's infant daughter to Khun Ying as her own. The third wife was jealous of Yen and caused problems for her, leading Praya Sihayotin to strip Yen of her title, and return her to be a slave. As her daughter grows up spoiled by Khun Ying, Yen suffers as a slave.