Hekla and Freya live at Poshington Hall Farm in the Lake District. They look like many sheep with silly smiles, beautiful woollen fleeces and horns, but they are not. They are in fact Icelandic sheep that possess secret troll-given magical powers in their fleeces and go on wonderful adventures.

In this book, the sheep join forces with the Spectral Army of Mungrisdale, their friendly Icelandic Lilts troll, and the ghosts of Poshington Hall to stop partying, greedy, flesh-eating trolls helping themselves to the sheep and residents of the Farm and Hall.