When a messenger bat arrives at the RSPCB, Ulf receives warning that beasts are in trouble in the wild. Unaware of the danger he is facing, Ulf sets off on an expedition to investigate. With the help of a little goblin named Gumball, he soon uncovers foul play - a rare colony of trolls is being smoked out from their caves to be used in an evil beast-hunting range. It's up to Ulf to stop the troll hunt. The future of the RSPCB depends on it...