There are two things you need to know about Susie. She is a young girl who is always interested in everything, and she always wears a ribbon in her hair. When she is thinking, she twiddles and pulls at the ribbon, until she works out what she has to do. At the moment, Susie is very interested in what Mr Green, the teacher, is saying about things going missing at school. Susie is also interested in a new girl who has been seen hanging about near the library. Susie does not know this girl, she is a stranger. Has the girl been taking things, or is she completely innocent? If it's not her, then who is taking things from the library? Join Susie as she tries to solve The Mystery of the Missing Books.