The Devil's Arithmetic — Jane Yolen

"I know where they're taking us."

HANNAH DREADS going to her family's Passover Seder. Her relatives always tell the same stories, and Hannah's tired of hearing them talk about the past. But when she opens the front door to symbolically welcome the prophet Elijah, she's transported to a Polish village -- and the year 1942. Why is she there, and who is this "Chaya" that everyone seems to think she is? Just as she begins to unravel the mystery, Nazi soldiers come to take everyone in the village away. And only Hannah knows the unspeakable horrors that await.