Bill is cooking when Graeme and Tim return from chess championships. Graeme and Tim are hungry, and want their dinner — however, there is only soggy lettuce and potato peel to eat because Bill has fed their normal food to "Bunter", a guinea pig, with dessert to follow. When Bill explains to Tim and Graeme that he is being paid £30 to look after the guinea pig, and the thought of being able to get some extra money leads to the Goodies setting up the office as the "Goodies Animal Clinic" for "loony animals". Graeme sends Tim and Bill out to collect them from their owners. The Goodies' animal "patients" include a gigantic-sized snake, a gold fish, a hen, a large dog, a bushbaby, a tortoise, a mongoose, a vampire bat, two singing dogs, and a tiny fluffy white kitten called "Twinkle". Graeme's specially formulated growth mixture, which he feeds to the kitten, causes Twinkle to grow to super-size proportions. Graeme keeps Twinkle inside to stop him from wandering, but Bill decides to let Twinkle out for the night. Graeme, speaking with desperation in his voice, says urgently: "Come on. We've got to find him and catch him before he eats someone he shouldn't." The following morning, Twinkle destroys St Paul's Cathedral and the Post Office Tower, as well as squashing Michael Aspel with his huge paw, and frightening various people and dogs. Graeme makes an antidote to counteract the disastrous effect of his growth mixture and reduce Twinkle back to the normal size of a cat, but the Goodies have to disguise themselves as giant mice, and become airborne on their trandem, to be able to get close enough to Twinkle for the antidote to be successful — following which their "hot-air trandem balloon" is carried away by a Concorde airliner. Twinkle returns to normal size, and all seems well. However, the Goodies discover that there is yet another unexpected and unforeseen consequence resulting from Graeme's growth mixture — they now have a king-size mouse problem on their hands.
Award
A special episode, which was based on the original 1971 Goodies' "Kitten Kong" episode, was called "Kitten Kong: Montreux '72 Edition", and was first broadcast in 1972. The Goodies won the Silver Rose in 1972 for this special episode at the Rose d'Or Festival, held in Montreux, Switzerland.
