Fresh from their triumph against Dub in San Francisco, the girls are content to return to their normal lives, unaware that their fight against the darkness is not over.
Although they succeeded in destroying their previous adversaries, another threat has risen in a far away country.
This time, they must travel to Edinburgh to confront the darkest of all evils.
Will they succeed in fighting back the dark or will they be left irrevocably changed?
As the conclusion to the original trilogy, this adventure will set the course for everything in their lives and they will learn that even their friends may not be entirely what they seem.