Leaving behind the security and modern conveniences of their Boston suburb, Jimmy, Pollyanna and the children heads to the wild west, where Jimmy has taken on the supervision of the building of a dam. Pollyanna's eastern friends felt that she had made an appalling sacrifice. But she loses no time in finding new interests, making new friends, and winning new adherents to her sunny philosophy. She starts a lending library, which helps ease the drudgery and hardships of life of the mountains people by expanding their worlds through literature and makes the ranch house became a center of helpfulness. Sundry love affairs received timely aid and the Pendleton youngsters absorb their new environment wholeheartedly.