Jo's secret haven is the beautiful garden of the big house nearby - until it is sold to a property developer who plans to cover it with houses and flats. In her efforts to save it she finds herself tangling with a very mixed collection of neighbours, struggling to find her way around the unreasonably big Town Hall, having to deal with the secret problem she thinks of only as It, learning quite a lot about her own family and getting some unexpected help from a long-dead ancestor.