Based on Marcia Davenport's novel and set in 1870, Valley of Decision details the romance between a housemaid named Mary Rafferty (Greer Garson) and her employer's son, Paul Scott (Gregory Peck). Paul's father, William (Donald Crisp), owns a Pittsburgh steel mill where Mary's father, Pat (Lionel Barrymore), was crippled; Pat believes he wouldn't have suffered his accident if William had taken more safety precautions. Once Mary and Paul fall in love, both fathers fight against their relationship, and soon their romance is plagued by not only familial tensions, but also a worker's strike at the steel mill.