OK, this is a real Doper’s test.
I saw this B/W | Color(?) movie several times in high school, as part of the cirriculum.
IIRC, it takes place during the Civil War. A condemned man is sentenced to death by hanging. He is brought to a railroad bridge over a stream where he is made to literally walk the plank. As he stands on the end of the plank, soldiers on the other end step off and he is hanged.
However, either the rope breaks or is too long and he plunges into the river. We see him struggling to free his hands and coming to the surface, where soldiers starting firing on him.
The rest of the movie is his trying to escape his pursuers. We find near the end he is trying to reach his beloved living on a traditional Southern Plantation.
So as I will not spoil it for those who never saw the movie, I’ll stop here.
For the life of me I cannot remember the movie title. I don’t know if the movie is even shown in schools anymore.