Meet Mr Monkey, who belongs to Class Two. He's more than just an ordinary toy. He's magic! No one can quite remember now how long he's been at the school or where he came from, but once a week one of the children has to take him home and write a diary about their time with him. Ben can't stop Ian from Class Five taking his things. But when he's given Mr Monkey to look after, Ben finds out that Mr Monkey knows lots of clever tricks to cure Ian of being so mean...