Joseph doesn't remember much of his father, except the passion for nature and animals that they share. One dark and stormy night, he suddenly learns that his father was not just the famed zoologist he believed him to be, but also a mythozoologist, whose journal is packed with discoveries about the creatures of myths and legends!

Joseph struggles to believe any of it; his father had surely dealt with facts, not fiction! Yet, when he frees an impolite hobgoblin trapped in a hunter's cruel cage, he soon discovers the truth of the matter. Not only that, but he, his friends, and the hobgoblin are forced to band together on a chaotic journey across Somerset - encountering dangerous beasts and beings along the way.

Whilst they struggle to avoid curses and being eaten alive, they race to return the hobgoblin and his extraordinary key to the magical isle of Avalon. Can they make it before the evil hunter La Hyène captures them, or will the hunter take the key and march into Avalon to plunder the greatest treasure of them all?