"The Fifteenth Character"

I read this book called The Fifteenth character.
Sally Brown is a student and works at Happy Hills in her holiday. She wears the costumes.
One day Zapp who is famous singer came to the Happy Hills and his important CD was stolen by someone. Some police mans came there and checked all visitors but they couldn't find it.
Sally was looking at "Jobs for today" and noticed that there has to be 14 characters, but there are 15 characters in the room.
The police found weird character and took off its heads. She had a CD.
Sally and her friend got Zapp's concert tickets for free and enjoyed his concert.

I was glad that Sally found out who stole the CD, because she loves Zapp's music and everything, and I can see how her feeling. But I was kind of desappointed that he was mad and yelled at everyone about the CD though.