Iroha Tamaki woke up in a witch’s labyrinth in a bedroom which looked liked hers except the door to the room was locked and then she hears a voice.

“Hey big sis also I know you’re awake and you can’t use your powers in here this bedroom blocks you from transforming.”

It was Ui’s her younger sisters voice and her sister had turned into her witch form Shitori Egumo to prevent Iroha from leaving.