It's 1977 and Cassie Lyman, a graduate student in women's history, is struggling to find a topic for her doctoral dissertation. When she discovers a trove of drawings, suffrage cartoons, letters, and diaries at Smith College belonging to Kate Easton, founder of the Birth Control League of Massachusetts in 1916, she believes she has located her subject.
Digging deeper into Kate's life, Cassie learns that she and Kate are related—closely. Driven to understand why her family has never spoken of Kate, Cassie travels to Cape Ann to attend her sister's shotgun wedding, where she questions her female relatives about Kate—only to find herself soon afterward in the same challenging situation Kate faced.