The Queen of Tancred and her royal retinue are on a mission, to ensure all the citizens of Tancred are happy. But that's a lot harder than it sounds, especially when the Happiness Tour accidentally stumbles into the neighbouring region of Hamelin. Oops. Soon, Queen Mathilde smells a rat. A whole kingdom of them, in fact, because Hamelin has been overrun with rodents. Why is a rat on the throne? Where are all of Hamelin's children? And what is happiness anyway?