Lord Goth believes that children should be heard and not seen, so Ada has to wear large clumpy boots so that he can always hear her coming. This makes it hard for her to make friends and, if she's honest, she's rather lonely. Then one day William and Emily Cabbage come to stay at the house and, together with a ghostly mouse called Ishmael, the three children begin to unravel a dastardly plot that Maltravers, the mysterious indoor gamekeeper, is hatching.

Ada and her friends must work together to foil Maltravers before it's too late!