Mandy Hope loves animals more than anything else. She knows quite a lot about them too; both her parents are vets and Mandy helps out in their surgery, Animal Ark. When Animal Ark's receptionist, Jean Knox, returns from the shops, she brings back more than she bargained for: a chinchilla has crept in with her shopping! Before it can be caught it shoots off to hide, Mandy and James must find it—but there's no sign of the chinchilla anywhere!