When Alice Paul of the National Woman's Party asks Mary Nolan to return to Washington, D.C., to demonstrate again for women's right to vote, Mrs. Nolan immediately packs her bags for the trip. Her family decides that because of her age and health, someone should go with her. Everyone agrees, but no one is available except granddaughter Delia whose relationship with her grandmother is strained. Her unmentioned assignment is to keep Grandmother from being jailed-again.

On the train to Washington, Delia is introduced to army Captain Richard Manning. The captain calls on Delia in Washington and, despite a cool reception from Grandmother, a motorcycle wreck, and the prospect of separation, romance blossoms.

At the boarding house where Delia and Grandmother stay, Delia meets Frances Dove, a nurse returning from the battlefields of France, who tells Delia of a friend's romantic betrayal and death.

Countering this is Delia's friendship with Eloise Brown, a volunteer at NWP headquarters, whose budding romance with the neighborhood baker and plans to be an independent woman inspire Delia to chart her own course.

Delia's interest in the suffrage movement is kindled when she meets Alice Paul and other women at the NWP headquarters. A chance encounter with Mary Church Terrell of the National Association of Colored Women; learning of Margaret Sanger's fight for women's reproductive rights; trying to convince Florida U.S. Senator Duncan U. Fletcher to vote for the Susan B. Anthony Amendment; and experiencing first-hand the horrors of the Washington, D.C., jail all transform Delia from a naïve girl into a mature young woman.

By the end of the trip, Grandmother Nolan and Delia's relationship has changed as they have bonded through shared experiences.

Parting ways in Jacksonville, Florida, Grandmother Nolan and other suffragists continue on their national tour aboard the Freedom Train, as Delia begins her journey home to Fernandina and into a new era opening for women.