Mona is fourteen years old, an orphan, and learning the art of baking from her aunt. She'll inherit the bakery, someday.
Oh, and she's a wizard.
Not a great, powerful wizard, like the ones who defend the city. She can't throw lightning bolts, or talk to water. She can, however, get dough to do amazing things. Sometimes she makes the gingerbread men dance to entertain the customers--although some customers get more nervous than amused. Her familiar is her sourdough starter, Bob. Bob can be a little scary, for people who aren't Mona, but he stays in his bucket in the basement, and it's mostly Mona who deals with him. It's a peaceful, productive, enjoyable life.
Then one morning, she comes in to start the baking for the day, and finds a dead girl in the kitchen. She wakes her aunt and uncle, her uncle fetches the constables.