Publisher's Synopsis
This is one volume in the Moonstones series of stories for 8 to 12 year olds. Each story has an element of mystery or adventure, with a strong storyline, and is suitable for the multi-cultural classroom. Marina and Joff are left in the charge of their three-year-old sister's domineering and sinister babysitter while their mother is abroad. As they struggle to cope, they are drawn into the fantasy world of Psi, an underwater city of their own invention. Their encounters there mysteriously mirror their own lives, and it is soon clear that their problems won't be solved unless they can help their counterparts in Psi.
