A live action puppet series.

When  young Roger Becket crashes his bike into a valley of strangely- shaped rocks he finds that a group of equally strange trolls become instantly convinced he is their long-awaited leader. During his regular visits to this hidden valley (which also contains a delusional  sheep who has a rare talent for martial arts) Roger introduces many elements of life in his own world to his new subjects which the Rottentrolls then try and make sense of in theirs. Everything from sport to politics to school bullying to incredibly expensive trainers is refracted through the crazy, innocent, perceptive eyes of the Rottentrolls, so the teacher usually ends up learning the lesson.  As Roger grows older, his younger sister Kate is given the crown of princess and the stories resume via her visits.