Hana notices that some of the teachers whisper when she passes by. She hears about the magic of erasing memories and tells about it to her friends.
Hana goes to the forbidden library to find a book about it and reads that the people that used this magic can never use it again, and has to give away one of their cherished memories as well. When they try to think about that memory, they will have an extreme headache.
One day, the headmaster of Hogwarts (not Dumbledore) and the students ask questions about the rules and life at Hogwarts. A student asks the headmaster about his first day at Hogwarts and he suddenly screams, having a headache.
In the mirror that shows the past, Hana sees her father wearing the Hogwarts uniform and realizes that the headmaster erased the memories of her father. Starting from this moment, she keeps on feeling that something is calling her.
Hana follows the feeling that is calling her and goes to the forest. There she sees one of the Hogwarts teachers that was always with the headmaster. That teacher knows that the headmaster erased Hana's father's memories and notices that she is going to the place where other wizards are hiding, and tries to kill her.
At the moment Hana is in danger, one wizard comes and helps her and leads her to the place where all the wizards who were expelled by the evil headmaster were hiding. They were who called Hana and they were trying to overthrow the headmaster and go back to their places again. Hana joins them.