When the Nazis invaded France in 1940, Marion and Huguette Müller's family was torn apart. After their mother was deported to Auschwitz, the two young Jewish women fled to the Alpine skiing town of Val d'Isère, where they were rescued by an incredibly courageous doctor.

Through intrepid reporting, sensitive family interviews, and thousands of records, Rosie Whitehouse traces decades-old mysteries of the Müller sisters' story, seeking closure and justice for her family and the doctor's. Why did he shelter them? Who had betrayed their mother? How did this national tragedy happen?

Whitehouse's discoveries raise deep moral questions about France's Holocaust, with urgent resonance for today's politics: questions about French complicity, minority agency, collective culpability, duty to your country and duty to other people. She pieces together not only how the sisters were saved, but how so many others were lost.

From villagers to Vichy officials, antisemitism to resistance, this is a sweeping yet intimate history of French choices before, during and after the Nazi occupation; and a moving, gripping tale of forged documents, narrow escapes, one family's trauma, and the grace of human connection.