Indigo McCloud's sister Peaches is every adult's favourite child: pretty, golden-haired, polite and charming. But the children of Blunt know better: Peaches and her sisters are a gang of bullies who will stop at nothing to get her own way.

This is the story of Indigo's battle to stop Peaches. Leaping across the rooftops of Blunt, talking to his best friend, computer genius Polly, though a walkie talkie, Indigo tries to keep one step ahead of his sisters. But he has to tangle with deadly spiders, curry farts, bungling policemen, various kidnappings, a submarine mishap with a villainous wigmaker ... When he discovers a hidden basement under Peaches's room where she and her sisters plot their schemes, he knows he is up against a truly evil genius.