The headstrong beauty Marcella Boyce, who has acquired radical political views while at school, returns home and becomes engaged to Aldous Raeburn, the son of her father's neighbor Lord Maxwell and a moderately conservative politician and landowner. Marcella champions Jim Hurd, a local poacher accused of murder (who is prosecuted by Raeburn): she nurses his grieving wife and dying, consumptive son and arranges his legal representation by Edward Wharton, a Socialist politician and Raeburn's romantic rival.
After Hurd's execution, Marcella breaks off her engagement, trains as a nurse, and turns her reformist efforts toward the London poor instead of the rural poor in rural villages. She refuses Wharton's offer of marriage and finally accepts Raeburn's hand.