The plot: the biracial daughter of a wealthy Canadian family (father is black, mother white) falls in love with and married a white American. They decide to live in the United States, but it turns out the man is a villain who ends up raping her and selling her into slavery in the south. The parents become worried when there is no word from their daughter and begin to search for her, eventually finding out what has happened and getting her and another slave she has fallen in love with back north through the underground railroad.

Captive Heart: The James Mink Story (1996) (TV)

Seems to be Captive Heart: The James Mink Story.

ETA: Alas, I was three minutes too slow. Perhaps I could've typed faster without a cat sitting on the keyboard.

Wow you guys are amazing. How did you do that:)