Addy's mum is expecting a baby, and Addy is not pleased. When she isn't pleased, the becomes 'the baddy'. No one is interested in her anymore; all they want to talk about is the coming baby. Addy is naughty at school and pulls the cat's tail at home, but finally decides the only way to gain attention is to run away. The short-lived attempt to do so results in her discovery that being a big sister might be fun after all. Lively coloured illustrations help make this short read great fun. The plot is unusual in that Addy's jealousy occurs before the baby is born.