Hannah writes on herself because she wants to copy the prominent tattoo that her grandfather has on the inside of his lower arm. When the story opens, Hannah is too young to understand the significance of the blue numbers on the inside of her grandfather’s wrist. This tattoo fascinates her, as does his wringing his arms and highlighting the mark when he gets upset.

One evening when she wants some attention, she mimics the mark on her own wrist, drawing the tattoo in ink. She is surprised that her actions evoke such a severe response from her grandfather and other relatives.

In her dream, she goes back in time to World War II and the Nazi era. She becomes Chaya, a distant relative for whom she was named. Chaya and the others in her small village are rounded up by the Nazis and deported to a concentration camp. It is there in the camp that Hannah learns about why her grandfather has the tattoo on his arm, and she recognizes its horrible significance. With the benefit of her knowledge from modern-day America, she tries to warn others about what their fate will be in the camp, but they either does not want to listen to her or cannot because it is too horrible to imagine that she is right. What started as a childish prank to get her family’s attention becomes a life lesson for her as she imagines herself a prisoner in the concentration camp who is about to get tattooed, becoming a mere number and not a human being.