Dr. Eli Watt, once an ambitious physician with a promising New York practice, returns with his young son Jimmy to his hometown of Willow Springs, widowed and broke. After mortgaging the family house to unsympathetic banker John Radford, Eli sets up practice in Willow Springs and is soon called on to deliver a baby. When the mother dies after giving birth to a girl, the father, McGinnis, accuses Eli of malpractice and refuses to care for the baby. Eli brings home the child, whom he names Letty, and, while tending tirelessly to the medical needs of the highly critical townspeople, who pay him only with home-grown food, rears her as his own. Four years later, a reformed McGinnis begs for the return of his daughter, and against the admonitions of Sarah, his housekeeper, Eli sends Letty home with her natural father. When a smallpox epidemic ravages Willow Springs many years later, Eli singlehandedly curbs the disaster and improves living conditions in the rural New England community. Although commended by the county medical board for his efforts, Eli continues to practice in obscurity, while a now-grown Jimmy prepares to attend medical school in Vienna. Letty, meanwhile, falls in love with Radford's son Bill, who after a night of making love to Letty, is injured in an automobile accident. Eli assists in an operation to save Bill's arm, and his skills come to the attention of Dr. Tillinghast, a respected surgeon from New York. Impressed by Eli's abilities, Tillinghast invites his colleague to work and study with him in the city. Although greatly tempted by the offer, Eli misses his opportunity to go to New York when, instead of catching the train, he chooses to help a pregnant Letty, who has attempted suicide because Bill's father has denounced her as a gold digger. Six years later, Jimmy has earned his medical degree and Letty and Bill have married and had another child while Eli has remained the country doctor. Devastated by the realization that Bill is involved with another woman, Letty refuses to fight for her life after a difficult third pregnancy. Sensing the couple's troubles, Eli saves Letty's life once more by gently reuniting the family at Letty's bedside and inspiring her to fight. After being honored at a prestigious banquet, Eli then saves Jimmy's engagement to Joan Stockton by showing his ambitious, compassionless son the link between human kindness and effective medicine.