There was once a small mouse in a small town called Salem, at the edge of the wilderness. The mouse was named Maus Kraus. She was a very smart maus; she knew how to sew, and she went to school every day with her great friend Catherine, who was the teacher in the Girls School. Sister Catherine called her Sister Maus, and ... this new story tells how Sister Maus learned about Christmas and discovered other ways, indeed, to be useful.