After Alexandra is forced to leave her daughter behind after she is diagnosed with a threatening illness that would surely kill her, Henrietta, who goes by Heather, is raised by Roger and Brianna MacKenzie in 1980s Scotland. Naturally athletic, Heather learns about her origins, and decides to time travel into the days of the Revolutionary War to prove herself. However, only men are permitted in battle, and, when she runs into Captain Lord Ellesmere, things do not go as planned.
William Ransom is devastated after Jane Pocock takes her own life, vows never to love anyone ever again. However, he is stunned to encounter a woman dressed as a man near the camp of the Continental Army, and, after a swordfight, brings her to Claire Fraser for medical treatment. William is later roped into taking his adopted half-sister to their father and her mother in Philadelphia; however, at a ball to celebrate the reunion between Lord John Grey, his wife, and their long-lost cousin, sparks fly between William and Henrietta, which could lead to both their undoings.