Slap bang in the middle of the coldest Friday of the coldest week of the year, the central heating breaks down at Melton Mowbray Zoo. The system needs a new flange but flanges can't be obtained on Fridays in Melton Mowbray, so Mr Pickles the head keeper asks all the other keepers to take the animal they are in charge of home for the weekend. The results range from disastrous to successful: when the penguin (who 'always hankered after the good life') decides to eat his tea in Mr Pumbles' bed, and the lion succeeds in scaring off Mr Leaf's mother-in-law to such an extent that she doesn't come back to lunch for three years?