Miss Moffat is a spinster schoolteacher who inherits a house in a Welsh mining town. She finds the miners living in squalor and ignorance, and is determined to open a school to teach not only the children but also anybody from the village interested in learning. Aiding her is Mrs. Watty, a reformed thief, the young spinster Miss Ronberry, and John Goronwy Jones, who looks after the house. There is resistance to the idea of a school. Miss Moffat discovers Morgan Evans, a young man with a brilliant mind who works in the coalmines. In an essay he writes about being in the mines underneath the fields where "the corn is green." Morgan becomes her prize pupil, and Miss Moffat pushes him to try for a scholarship at Oxford. Unfortunately the pressures of everyone's expectations makes the boy snap and he has an unfortunate affair with a local girl that will require an additional sacrifice on the part of his teacher in order for them to realize their dream. But when he returns from Oxford and has seen what is out there, he refuses to be sent back to the life he knew in the mines.