Dave the wolf has been suffering from a mysterious illness, and the keepers have to make a tough decision. He was born 13 years ago at the park and was an unabashed troublemaker, forever trying to dodge patrol vehicles in an attempt to get out of his enclosure. He is adored by the keepers, so losing Dave would be heartbreaking. Worse still, he would leave his brother Alf behind. They have never been apart, so there's a chance Alf would struggle to survive as a lone wolf. The vets perform surgery on Dave as the keepers wait nervously for the results. Could this be the end for one of the park's biggest characters? Elsewhere, there are some new additions to the park's wallaby neighbourhood. Life has always been a soap opera for this lot, with break-ups, make-ups and babies aplenty. So four new feisty wallabies, including a hunky new male, are certain to freshen up this long-running drama. The keepers need to get them microchipped and wormed, but first they have to get hold of them! However, it's action stations when a runaway wallaby hops out of his paddock. Ben spends time with two of the park's grumpiest girls, the hippos. Jean Johansson helps the keepers perform a life-saving goat pedicure and also feeds the red-handed tamarins a new menu.