Donald is now well-known as a zoo vet, and is travelling the country dealing with circus animals, but still finds time to deal with the Great Northern Zoo's animals. The Northern Zoo itself is having a rough patch with Paddy acting as senior keeper and manager, and doesn'thold any illusions as to what is going to happen to the zoo. Maurice is annoyed about the amount of time Donald is away from the practice, and is even more annoyed when Donald informs him of a proposed safari park he will be involved with. Things finally come to a head when an elephant escapes from Ben Bishop's circus and injures a man, and forces Donald to split up the partnership.
Donald encounters a hostile lion trainer at the proposed safari park and is called in to treat three tiny alligators at a local night club.
Donald investigates the strange behavior and requests of an Italian couple with a trained dog act who are waiting out their quarantine at the zoo, and Ethel formally joins Donald at the safari park.
Donald helps prepare a dog for burial and meets an American dolphin expert.
Donald and Paddy battle a callous administrator as they struggle without much success to place all the zoo animals before the closing day.
Donald solves the riddle of vandalism in the village and an attack on a local vagrant, and provides a home for a laboratory baboon due to be put down.
Donald has trouble with the big cats:a lioness escapes, a tiger cub needs hand rearing, and a self-appointed expert insists on one to one contact with the pride.
Paddy and Donald settle the dolphins into a temporary home in France while Maggie tries to deal with practical problems at the park.
Maggie's a little prickly over the dolphin trainer Sindy but helps Donald cope with a mysterious epidemic running through the park's new lions.
Sindy and Donald journey to America to escort home the park's newest attraction-a killer whale named Cuddles.
Donald must learn quickly about the medical needs of killer whales when Cuddles begins losing blood, and he accepts some unusual help from the spirit world to treat a tortoise with inflamed eyes.
Donald has to find a suitable home for two baby elephants donated at the last moment by an old friend of Lady Anne, deal with all the confusion of the grand opening ceremonies for the safari park, and react to Maggie's intention to take a nursing job in the Middle East.