Nine months after the events of Tree Magic, Rainbow is struggling to come to terms with how she s changed. Her bond with trees has grown, but now they re under threat from the Tree Slayer. To save them, she ll need to leave everything she knows and loves. It will be her greatest adventure yet but she cannot succeed alone. She ll have to enlist the help of Eole, an enigmatic scientist and sceptic. Does Rainbow have what it takes to face the Tree Slayer? And can she trust Eole, who has powers of his own?