Charlie Bone and the Castle of Mirrors (Children of the Red King, #4)
by  Jenny Nimmo

5 out of 5 stars

Charlie’s friend Billy has finally been adopted, but Charlie worries that Billy’s new family are more like jailkeepers than loving parents. Billy is being held in a gloomy place called the Passing House, and it’s up to Charlie to break him out and find a safe place where Billy can hide. They think they can hide at the legendary Castle of Mirrors since it used to belong to Billy’s ancestor from hundreds of years ago, but they find something in the Castle of Mirrors that they didn’t expect and it changes everything for Charlie.