1838, England: When eighteen-year-old Frances Dickinson impulsively marries Lieutenant John Geils, all her hopes for her future are quickly shattered as she finds there is much about her husband she did not know. A cruel and violent man, John keeps Frances in isolation on his family's estate, while spending her fortune and preying upon their maids.

Frances yearns to break free from her marriage but the law is not on her side. Only when John's abuse escalates can she set in motion a daring plan to secure her freedom.

A story of gaslighting, control and one woman's fight, An Idle Woman is the true story behind one of the most sensational divorce trials of the nineteenth century.