Zarlak has captured small beings called ""the tricky trolls"", but one escaped and come to the kids. Zarlak then send his dragon to steal their magic book, but took Verne (who turned into into UBOS) instead, then they kidnap Gus, leaving Cassy to save the day, who is having a hard time using her shape-changing powers. Will she be able to save the day by turning into Zarlak?