"Sarah's Key" by Tatiana de Rosnay is a powerful and emotional tale that delves into the dark history of the Vel' d'Hiv Roundup in 1942, through the eyes of a young girl named Sarah, and uncovers a shocking secret with far-reaching consequences in the present. This captivating book intertwines past and present, shedding light on a forgotten chapter of the Holocaust and the impact it has on the lives of those involved.