Charlotte and Rose arrive home from school to find their kitchen covered in stinky, orange slime and their parents missing. To rescue them, the sisters use a magical book to travel to the sparkling, underground land called Gem. There they must find alternative sources of magic for the five Heart Duties that make life in Gem possible. With the help of the book, a dragon and two little fairy lights, can Charlotte and Rose track down a new source of magic for the first Heart Duty?