Legacy - Danielle Steel

Working at Boston University, Brigitte Nicholson lives a steady and comfortable life - she never takes risks.
But then she loses her archaeologist boyfriend, and her university admissions office job in the span of two days.
Her cautious lifestyle is set to change when she agrees to help her mother in researching a family history project.
Brigitte discovers a mystery in their family's past: a Dakota Sioux princess had been buried in Brittany as a noblewoman, alongside a distant relative.
Brigitte's quest to learn the story of this spirited and courageous relative, the Marquise de Margerac (NEE Wachiwi), takes her to France, where she uncovers the mystery of Wachiwi's existence.
As Brigitte's fascination becomes her obsession, her safe, secure existence changes into an exciting adventure.