Jimmy Driftwood a teacher wrote many of his songs about important events in history and gave his students musical lessons. I believe that this song is about the underground railway often led by Harriot Tubman. The slaves had chains, moved at night in moonlight and hid in daylight. Food was scarce and those that housed or fed them were at great legal risk and the slaves knew it. The song was done by Odetta and PP&M, I love to play and sing it.
Dave Wallerstedt