In the farming regions of the Midwest, Naomi Kellogg falls in love with Joe Copeland, the son of a neighboring family, though they must meet secretly at a brook between their farms because of a disagreement between their families. Joe, however, loses his life in a harvesting machine accident, and when Naomi's parents learn of their secret love, they are outraged at the violation of their strict moral code and insist that she accept the marriage offer of Caleb Evans, a man of righteousness. After the marriage, a child is born to Naomi on their western ranch, and she devotes her life to young Brook. When Brook falls in love with Tony, Naomi encourages her to elope with him though Caleb indignantly opposes the match. When Naomi reveals that Caleb is not actually the girl's natural father, Brook rejects her mother's affections and turns to her father, who convinces her that she should go to China as a missionary. In the East she becomes fascinated with impulsive Eric Helge, freely accepting his love. Later she is repentant, but upon receiving a stirring message from her mother, who in the interim has died, Brook decides to defy convention and duty and hastens after Eric to embark on a new life.