In 1789 Maine, a man is found frozen in the Kennebec River. Respected midwife and healer Martha Ballard is summoned to examine the body and determine the cause of death. Her private diary, a meticulous record of births, deaths and crimes, soon places her at the centre of a murder investigation intertwined with an alleged rape she documented months earlier. As a brutal winter closes in and a trial approaches, Martha’s quiet authority and refusal to bend to patriarchal power structures put her family, reputation and safety at risk.