Mum is introducing Jim to his new sister Jane, but Jim would like to trade her for a hamster! Mum is horrified, and Jim gets more and more fed up. No one has time to read to him or make him eggy soldiers. Then one night, when Jane is crying, Jim creeps into her room, intending to tell her 'what is what'. She is so pleased to see him that he ends up asleep in the cot with her. All this is done in rhyme, and the combination of the clever and all-too-true-to-life poems and the gentle comic-style pictures make this a winner.