Civil engineer George Castleman leaves his wife Mildred in the city and goes South to supervise the construction of a railroad. Not one to be alone for long, Mildred quickly begins an affair with the wealthy and dissolute Arnold Morgan, while George becomes friends with Zell, who lives in the mountains. When George tells Zell about his unhappy marriage, she goes to Mildred, hoping to bring about a reconciliation between her and George. Mildred, however, views Zell's relationship with George as the grounds for divorce that she has been trying to find for so long. She and her lawyer follow Zell back to the mountains, but they die in an accident en route. Zell and George then realize that they love each other and make plans for their life together.