Deep in the ancient forest of Hagwood, the dark forces of magic are gathering. The High Lady of the Hollow Hill is seeking to trap a thief who has stolen her most precious possession. She has summoned the nightmarish thorn ogres to claw it back.

But the High Lady has reckoned without the werlings - a little forgotten people whose magic of shape-changing has always kept them safe. Suddenly they are caught up in the High Lady's desperate hunt, and the terrible might of the thorn ogres is turned upon them. What can save the werlings now?