Mandy, Rene, Con and Splinter are all in the same grade at school and live in the same block of flats. They have nowhere to play and the so called park over the road is only a moderate-sized triangle of grass called The Beatrice Binker Reserve which is not even big enough for a game of soccer. They also have the grumpy and verbally abusive Mr Drake to deal with.
"...aren't you the same kids I have already told of yesterday for chalking arrows all over the footpath you need a good belting the lot of you and you girl yes you with the plaits what do you mean by leaning against my fence like that blocking the sunlight from my dahlias eh speak up!"
Take a step back into the eighties to see what upper primary kids did without Play Stations, mobile phones and other electronic gadgetry. Irene has a speech to make at school so it's off to the local library, no world wide web. In the block of flats they have to creep up and down the stairs to deliver messages to each other, no texting. To alleviate their boredom they scavenge around the neighbourhood for building materials and build their own castle in the reserve. There are now two copies of this little delight with different covers in the classroom library.