In 1907, Dr. Lily Penleric (Janet McTeer), a professor of musicology, is denied a promotion at the university where she teaches. She impulsively visits her sister Eleanor (Jane Adams), who runs a struggling rural school in Appalachia. There, she discovers a treasure trove of traditional English and Scots-Irish ballads, which have been preserved by the secluded mountain people since the colonial period of the 1600s and 1700s. Lily decides to record and transcribe the songs and share them with the outside world.
With the help of a musically talented orphan named Deladis Slocumb (Emmy Rossum), Lily ventures into isolated areas of the mountains to collect the songs. She finds herself increasingly enchanted, not only by the rugged purity of the music, but also by the courage and endurance of the local people as they carve out meaningful lives against the harsh conditions. She becomes privy to their struggles to save their land from Earl Giddens (David Patrick Kelly), representative of a coal mining company. At the same time, Lily is troubled when she finds that Eleanor is engaged in a lesbian love affair with her co-teacher at the school.
Lily meets Tom Bledsoe (Aidan Quinn), a handsome, hardened war veteran and talented musician. Despite some initial resentment, she soon begins a love affair with him. She experiences a slow change in both her perception of the mountain people as savage and uncouth, and of her sister’s sexuality as immoral. Hoping to help share the culture of the mountain people with the wider world, Lily convinces Clementine McFarland (Rhoda Griffis), an art collector, to purchase a painting done by a local woman.
Events come to a crisis when a young man discovers Eleanor and her lover, Harriet, kissing in the woods. That night, two men set fire to the school building, burning Eleanor, Harriet, and Deladis out of their home and destroying Lily’s transcriptions of the ballads and her phonograph recordings. Rather than starting over again, Lily decides to leave, but she convinces Tom and Deladis to “go down the mountain” with her to make and sell phonograph recordings of mountain music. As they depart, Cyrus Whittle, a renowned professor from England, arrives on a collection foray of his own, ensuring that the ballads will be preserved in the manner that Lily had originally intended.