A group of misfit teens are the reluctant recruits to save the mystical island of Avalon. Magically empowered - and chained to the task - by a set of rings, and directed in their mission by a tight-lipped talking dog, they must stop the rise of King Arthur. But as they struggle to get used to their powers and each other, they're faced with an even greater challenge: the discovery that they may not be the good guys in this story.