The first horrifying experience Hannah has is when she opens the door for the prophet Elijah during her family's Passover Seder and somehow magically gets transported through time to World War II. It is horrifying because she is confused and shocked. She doesn't understand where she is or how she got there, and the connection to family history is not readily apparent to her. She does learn that she is being called Chaya, which is her Hebrew name because she was named after a friend of her grandmother. The wedding is a horrifying day because as Hannah is trying to make sense of her new life and starting to enjoy the people she has met and the wedding festivities, she realizes it is the year 1942. Hannah realizes that all of the people are in danger, and tries to warn them about the Holocaust. The rabbi says that God will protect them, and the men show up to take them away. The next horrible day is when Hannah is taken for processing, including the hair shorn and tattooing. She knows that she might die, and when she arrives at the camp she learns about the Devil's Arithmetic, the bizarre games of life and death played in the camps. Another bad day is when Hannah inadvertently gets Reuven killed. This day starts out bad because Hannah realizes she cannot remember her own past. This terrifies her so much that she begins crying, even though crying could get her noticed and sent to the gas chambers. When the commandant asks who Reuven's mother is, Hannah calls out that she is dead and Reuven is taken away to join his mother. Hannah feels very guilty. The last and worst day comes when the six men are killed because of recent escape attempts. Hannah watches, and remembers some of her own story, the future to these people, and tells it to her friends. A guard comes by and says that since he has a quota to fill and since they are talking and not working, he will send three of them to their deaths. Hannah is not chosen, but she changes places with Rivka, who will eventually be her grandmother. She later learns that this is why she is called Chaya, because Chaya saved her grandmother.