Based on the true story of the large Gilbreth family, this film follows Frank Gilbreth (Clifton Webb) and his wife, Lillian (Myrna Loy), as they raise their 12 children. Both renowned efficiency experts, Frank and Lillian face significant challenges in parenting such a big brood, often leading to humorous situations. Fortunately, the couple frequently receive assistance from their eldest daughter, Ann (Jeanne Crain), who often acts as a third parent to the many Gilbreth children.