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?