Paris, July 1942: Ten-year-old Sarah is brutally arrested with her family in the Vel' d'Hiv' roundup, the most notorious act of French collaboration with the Nazis. But before the police come to take them, Sarah locks her younger brother, Michel, in their favorite hiding place, a cupboard in the family's apartment. She keeps the key, thinking that she will be back within a few hours. Paris, May 2002: On Vel'd'Hiv's sixtieth anniversary, Julia Jarmond, an American journalist, is asked by her Paris-based American magazine to write an article about this black day in France's past. Julia has lived in Paris for nearly twenty-five years, married a Frenchman, and she is shocked both by her ignorance about the event and the silence that still surrounds it. In the course of her investigation, she stumbles onto a trail of long-hidden family secrets that connects her to Sarah. Julia finds herself compelled to retrace the girl's ordeal, from the terrible days spent shut in at the Vel' d'Hiv' to the camps and beyond. As she probes into Sarah's past, she begins to question her own place in France and to reevaluate her marriage and her life.