Loving Frank is the story of Mamah Borthwick and her love affair with a famous architect, Frank Lloyd Wright. Mamah is a highly educated woman who is feeling stifled by her loveless marriage. She married out of convenience rather than for love. Her husband is not on the same intellectual level.

When Mamah meets Frank Lloyd Wright, she finds a man who stimulates her intellectually as well as physically. She must weigh her love for her children and her love for Wright. Mamah runs away with Wright to Europe leaving her children behind. She loves her children, but she needs to have a life of her own. She wants to discover who she is and what she needs to do with her life.

Choosing Frank Lloyd Wright over her family causes a scandal in their Chicago suburb. Reporters attempt to follow the two and write stories of how they have abandoned their families. The couple's actions affect them and the families that they have left behind. Mamah’s children do not understand why she has left. It takes years for her to attempt to repair the damage that her leaving has done to her family.

Mamah risks much to have a life with Frank Lloyd Wright. She divorces her husband and loses custody of her children. She is only allowed to see her children a few months of the year, but she is happy to have them even then. Mamah is able to achieve the life that she dreamed was possible, a love that consists of physical and intellectual stimulation and the ability to have an identity of her own.

Mamah lives her life for her own happiness. She wants more out of life than to be just a wife and mother. She takes a chance on her love for Frank Lloyd Wright. This brings scandal on herself and her family. Mamah travels a hard road while searching for her identity and happiness. In the end, a madman destroys her life, her family, and her home. Ultimately, she loses her life.