Ray is getting used to life as Rainbow Grey - she now has ALL the magical weather powers at her fingertips, although she hasn't quite mastered them yet! When all of the cloud creatures start disappearing - including Ray's own beloved cloud cat, Nim - Ray and her friends have a mystery to solve. Ray is sure that a dark magic is behind the disappearances. Can she work out what is going on before cloud magic is lost forever and Earth is destroyed by the ultimate storm...?